Prenuptial Agreements in New Zealand: What Your Finances Are Really at Stake

Nobody starts a relationship expecting it to end. And yet roughly one in three New Zealand marriages does, according to Stats NZ dissolution data. De facto relationships, which now make up the majority of partnerships among younger New Zealanders, break down at rates no official dataset even captures.

By the end of this article, you will know whether you need a contracting out agreement (commonly called a prenuptial agreement or prenup), exactly which assets are exposed under New Zealand law, and whether the cost is justified. Most guides on this topic are written by lawyers. This one comes from the financial planning side, because a prenup is not just a legal document. It is a financial decision with compounding consequences for your wealth, your retirement, and your family.

The default position under the Property (Relationships) Act 1976 is a 50/50 split of all relationship property: the family home, KiwiSaver Scheme balances, vehicles, savings, and often business interests built during the relationship. It does not matter whose name is on the title or whose salary paid the mortgage. A contracting out agreement lets couples write their own rules instead. It is the only legally binding way to divide property differently from the statutory default, short of asking the Family Court to decide for you, an exercise in which legal fees of $30,000 to $100,000 or more are common.

What the Law Actually Says

The Property (Relationships) Act 1976 (PRA) governs how property is divided when a marriage, civil union, or de facto relationship of three or more years ends, whether by separation or death. The Act has applied to de facto couples since 2001, a fact still overlooked by many people who assume only married couples are affected.

Shorter relationships are not always exempt. Under section 14A of the Act, a relationship of fewer than three years can trigger the equal-sharing regime if there is a child of the relationship or if one partner has made a substantial contribution. A couple with a two-year-old child and an 18-month relationship can find themselves subject to the full force of the Act. Assuming you are safe because you have not crossed the three-year mark is a dangerous bet if children are involved.

Relationship property generally includes the family home (regardless of who owned it before the relationship), household chattels, vehicles, joint bank accounts, KiwiSaver Scheme contributions made during the relationship, and any investments or assets acquired while together. Debts incurred for the benefit of both partners, including mortgages, also fall into the pot.

Separate property includes assets owned before the relationship, inheritances, and gifts received by one partner, provided they have been kept genuinely separate. An inheritance deposited into a joint account, or used to renovate the family home, loses its separate status. The same applies to pre-relationship savings commingled with household funds. Good intentions do not survive poor record-keeping.

The Family Home Trap

This catches more New Zealanders off guard than almost any other provision in the Act. If one partner owns a mortgage-free home before the relationship and the couple moves in and uses it as their principal residence, the entire value of the home typically becomes relationship property. Not just the capital gain during the relationship. The entire value. A home worth $900,000 before the relationship started can become a $450,000 liability on separation if no contracting out agreement is in place.

The New Zealand Law Commission flagged this as a significant concern in its 2019 review of the PRA and recommended reform, including reclassifying pre-owned homes so only the increase in value during the relationship would be shared. Those recommendations remain in legislative limbo. The law, as it stands today, is unchanged.

Separate Property Is Not Always Fully Separate

Even if an asset is classified as separate property under an agreement, income derived from it, such as rental income from a separate investment property, may still be captured by the Act if it has been used for the benefit of both partners. More importantly for business owners, any increase in value attributable to the other partner's contributions can be claimed. Those contributions include indirect ones: managing the household and raising children so the business-owning partner can focus on the company. During financial planning, this distinction is frequently overlooked by clients who assume their pre-relationship portfolio or business is fully ring-fenced. It rarely is, without a properly drafted agreement.

What a Contracting Out Agreement Actually Does

A contracting out agreement, made under section 21 of the Act, lets partners define their own terms for property division. The agreement can cover some or all of their assets, including property not yet acquired. It can be signed before a relationship begins, during it, or at its conclusion, and it can specify how property should be dealt with if one partner dies, making it an important companion to your will and any trust arrangements.

In practical terms, the agreement might specify which assets remain separate property, how assets acquired during the relationship will be divided, what happens to a business one partner built before the relationship, how inherited wealth or family trusts are treated, and what occurs on separation. New Zealand's framework offers relative certainty here: a properly executed contracting out agreement under the PRA is generally treated by courts as binding, subject to the serious injustice override discussed below. This compares favourably to jurisdictions like Australia and the United States, where enforceability is far less predictable.

The Requirements: Getting It Right

A contracting out agreement is void unless it meets every one of these formal requirements:

1. The agreement must be in writing and signed by both partners.
2. Each partner must receive independent legal advice before signing, from separate lawyers.
3. Each partner's signature must be witnessed by their lawyer.
4. The witnessing lawyer must certify they have explained the agreement's effect and implications to their client.

Skip any step and the agreement is void. The court may, in limited circumstances, give effect to a void agreement, but relying on judicial discretion is an expensive gamble.

In practice, one lawyer typically drafts the agreement and the other reviews it on behalf of their client. The reviewing lawyer's role is not a rubber stamp. They are there to identify reasons their client should not sign, to suggest fairer terms, or to flag risks the drafting lawyer may not have addressed. As Community Law explains, the certification process exists because a properly executed agreement carries the weight of a court order and cannot easily be set aside.

Legal costs for a well-drafted agreement typically run between $2,000 and $5,000 per couple, depending on complexity. Couples with businesses, trusts, multiple properties, or cross-border assets will pay more. Measured against the cost of litigating a relationship property dispute in the Family Court, the upfront investment is modest.

Why Your Financial Adviser Sees This Differently

Legal commentary on contracting out agreements is thorough and largely excellent. What is far less commonly discussed is how these agreements interact with the broader financial structure of your life, and this is where a financial adviser adds a different kind of value.

A lawyer will draft a legally compliant agreement. A financial adviser will help you understand what is actually at stake before you sit down with the lawyers. This starts with preparing a comprehensive financial schedule: a complete picture of assets, liabilities, insurance, superannuation, and income across both partners. To make the most of this process, you should have the following ready:

• Bank and savings account statements for both partners.
• KiwiSaver Scheme balances and most recent annual statements.
• Property valuations or recent council rating valuations for any real estate owned.
• Business financial statements, if either partner holds a business interest.
• Details of any debts, including mortgages, personal loans, and credit cards.
• Insurance policies (life, income protection, health) and their current status.
• Any trust deeds, loan agreements, or gifting arrangements involving family members.

Arriving at a lawyer's office with this schedule prepared reduces billable hours, avoids the slow and expensive process of reconstructing financial information under time pressure, and ensures the agreement is built on accurate data rather than estimates.

Consider a couple where one partner holds a diversified investment portfolio worth $600,000 at the start of the relationship, and the other has a mortgage-free home valued at $800,000. Without a contracting out agreement, and assuming the relationship lasts beyond three years, both assets could become relationship property. Over time, the portfolio grows to $900,000; the home appreciates to $1.1 million. On separation, the statutory default would divide $2 million equally. (These figures are chosen for simplicity. Actual outcomes depend on asset classification, contributions, the terms of any agreement, and the specific circumstances of the relationship. Asset sizes vary widely.)

If your financial situation accounts for market downturns, illness, and redundancy, but not the possibility of separation, it has a gap. A contracting out agreement lets you ring-fence pre-relationship assets while agreeing how growth, income, and new assets are treated. This is not about distrust. It is a conscious financial decision rather than a default.

Who Needs One

If any of the following apply to your situation, the statutory default is unlikely to match your intent:

You own a home and your partner is moving in (see the family home trap above). You are receiving or expecting an inheritance, and the money will touch shared accounts or shared assets. You own a business, and your partner's indirect contributions, including childcare and household management, could give rise to a claim over the business's growth. You have children from a previous relationship and want to protect assets earmarked for them. Your parents are contributing toward a property purchase. Or you simply want to agree on financial expectations upfront rather than relying on statutory defaults.

The assumption persists in New Zealand and elsewhere that prenups are only for the wealthy or the cynical. Neither is true. They are increasingly common among couples entering second or subsequent relationships later in life, and among younger couples where one partner is entering the relationship with materially more than the other.

The Bank of Mum and Dad

Parental lending deserves particular attention, especially as New Zealand's great wealth transfer accelerates. It is increasingly common for parents to contribute toward a child's first home. If the child is in a relationship and no contracting out agreement is in place, a parental gift becomes relationship property the moment it enters the family home.

Parents should consider making a properly documented Family Loan Agreement or Deed of Gift a condition of the financial contribution, not an afterthought. A Deed of Gift is commonly required by mortgage lenders to confirm the money is not a loan, but a separate side-agreement between parent and child can clarify the intent to keep the funds as separate property. Encouraging the child to put a contracting out agreement in place before the money changes hands adds a further layer of protection. Without these steps, a parent's generosity may end up divided equally with their child's former partner. This is a conversation more New Zealand families should be having earlier.

The “Serious Injustice” Test

Even a properly executed agreement can be set aside if a Family Court judge is satisfied it would cause serious injustice. The threshold is deliberately high. Mere unfairness is not enough. The court must be satisfied the outcome would be seriously unjust, a distinction with real teeth. This means a well-drafted, regularly reviewed agreement is very difficult to overturn, which is the entire point.

The court will consider whether the agreement was unfair or unreasonable when it was made, whether it has become unfair due to changes in circumstances, and whether the parties intended to achieve certainty by entering the agreement in the first place.

In one notable New Zealand case, a couple signed a prenup in 1998 protecting the wife's $95,000 equity in her home. After 16 years together, the home had grown to approximately $350,000 in net proceeds. The husband had, at times, contributed the greater share of household income. The court found it would be seriously unjust for the wife to receive roughly 75% of the proceeds and set the agreement aside. The lesson: agreements drafted at the beginning of a relationship may not survive decades of changed circumstances unless they are reviewed and updated.

Most family lawyers recommend reviewing a contracting out agreement every three to five years, or whenever a major life event occurs: the birth or adoption of a child, one partner leaving work or significantly changing career, the purchase or sale of a major asset, receiving an inheritance, or any substantial shift in either partner's income or net worth. A review with your lawyer every few years costs next to nothing. Discovering your agreement is unenforceable 15 years later, in the middle of a separation, can cost six figures.

How to Have the Conversation

Bringing up a prenup is, for many couples, about as appealing as discussing funeral arrangements. The discomfort is understandable but misplaced. A contracting out agreement is not an expression of doubt. It is an acknowledgement that adults with assets should make deliberate financial decisions rather than leaving them to a statute drafted in 1976.

The most productive conversations happen early, well before a wedding or moving in together. Framing it as financial planning rather than relationship insurance helps. The discussion should cover what each partner owns and owes, what they expect to happen if the relationship ends, whether either partner has obligations to children from a previous relationship, and how inherited or gifted assets should be treated.

Some couples find it useful to work through these questions with a financial adviser before engaging lawyers. An adviser can prepare the financial schedule outlined above, identify gaps in insurance or estate planning, and help both partners understand their combined position. This groundwork means the legal process is faster, cheaper, and grounded in reality rather than guesswork.

A Note on Trusts

Trusts add another layer of complexity. New Zealand's Trusts Act 2019 tightened governance requirements and made it harder for trusts to operate as opaque vehicles. The courts have consistently looked through trust structures where assets were transferred with the intention of defeating a partner's relationship property claim. A trust alone is not a reliable form of asset protection. Combined with a well-drafted contracting out agreement, the position strengthens considerably, but neither should be treated as a substitute for the other.

Frequently Asked Questions

Does a contracting out agreement cover KiwiSaver?

Yes. KiwiSaver Scheme balances accumulated during the relationship are relationship property under the Act. A contracting out agreement can specify how these balances are treated on separation.

What if my partner refuses to sign?

A contracting out agreement requires both partners to participate voluntarily. You cannot compel someone to sign. If your partner refuses, the default provisions of the Act will apply. This makes the early, transparent conversation all the more important.

Prenuptial Agreements in New Zealand

A contracting out agreement is one of the few financial decisions where spending a few thousand dollars now can prevent a six-figure dispute later. It is not romantic, and nobody puts it on a wedding registry. But it is an act of financial clarity and personal ownership: choosing, deliberately, how your assets will be treated rather than hoping a 50-year-old statute will produce the right outcome for your circumstances.

If you are entering a new relationship with assets worth protecting, or you are already in one and have never had the conversation, the time to act is before circumstances force the issue. Not after.

Your financial plan might assume your assets stay yours. The law assumes otherwise. If those two things have not been reconciled, let's fix that. Talk to us about building a financial life designed for clarity, protection, and long-term financial freedom.

Important note: we’re a financial advice and investment management service provider, we’re not a law firm. To learn more about this area speak to a good lawyer who specialises in family law, as they’ll be able to ensure you’re aware of everything you need to know. They can also suggest the best way forward for your personal situation.