A recent Supreme Court decision has delivered one of the most important estate planning lessons New Zealand families have seen in years.
The case, Rimmer v Wilton [2026] NZSC 122, highlights a problem that many people do not realise exists: a relationship property agreement and an estate plan are not separate exercises. If they are not carefully co-ordinated, the consequences can be expensive, unexpected, and deeply divisive for families.
For families, particularly those in second relationships, blended families, farming businesses, family trusts, and multi-generational enterprises, the decision is a timely reminder that estate planning should never be treated as a “set and forget” exercise.
The dispute
David Rimmer died without a Will.
He was survived by his long-term de facto partner, Carolyn Wilton, and two adult children from a previous relationship. Earlier in their relationship, Mr Rimmer and Ms Wilton had entered into a contracting out agreement, often called a pre-nuptial agreement, under the Property (Relationships) Act 1976.
The question before the Supreme Court was whether Ms Wilton could receive both:
- the benefits provided by the contracting out agreement; and
- additional benefits available under New Zealand’s intestacy rules because Mr Rimmer had died without a Will.
The Court of Appeal said yes. However, the Supreme Court has now overturned that decision and concluded that, on the wording of the agreement, Ms Wilton had effectively contracted out of the right to claim further entitlement from the estate.
While the legal reasoning is important and acknowledged by the Supreme Court as a complex area of the law, the practical consequences are much more significant.
The real issue was not the agreement, it was the absence of an estate plan.
For many years New Zealand lawyers have treated relationship property planning and estate planning as related but distinct disciplines, assuming:
- A contracting out agreement answers one question: “What happens to our property if the relationship ends?”
- A Will answers another: “What happens to my assets when I die?”
The problem is that many clients assume those documents naturally work together. Often they do not. The Supreme Court decision demonstrates that they are inseparable.
When there is no Will, or when a Will has not been reviewed after a contracting out agreement is signed, gaps emerge. Those gaps create uncertainty. Uncertainty creates litigation. Litigation consumes estates.
Why this matters for families
Individual asset bases and situations are more complex than ever. Often we see factors such as family-owned businesses, orchards, investment properties, trusts, and blended families which impact succession planning. Many clients enter second or later relationships with substantial assets and children from previous relationships. Further, relationships amongst family can become strained.
There are often competing objectives:
- protecting children from an earlier relationship;
- providing security for a new partner;
- preserving family assets;
- maintaining fairness between beneficiaries; and
- reducing the likelihood of future disputes.
A contracting out agreement is frequently part of the solution. If the corresponding estate planning is missing, outdated or inconsistent, the intended outcomes can quickly unravel.
Common mistakes
Having a contracting out agreement but no Will
This was the central issue in Rimmer. Many people invest considerable time and money negotiating a contracting out agreement but never complete the corresponding estate planning. The result is that default statutory rules end up deciding how assets pass on death. Those rules may bear little resemblance to what either partner actually intended.
Failing to review documents together
A Will drafted 10 years ago may make little sense after:
- a new relationship;
- marriage;
- separation;
- acquisition of significant assets;
- establishment of a trust; or
- signing a contracting out agreement.
Assuming separation automatically fixes everything
Many people are surprised to discover that separation does not necessarily solve estate planning issues.
In New Zealand, separation alone does not automatically revoke a Will. Former partners can still feature in estate planning structures long after relationships have ended. That creates obvious risks where documents have not been reviewed.
Overlooking business and trust structures
Ownership arrangements, shareholder agreements, trusts, partnership arrangements, and succession plans all interact with personal estate planning.
A Will that ignores those arrangements can produce unintended consequences.
What should people do now?
The answer is not necessarily to rush out and sign new documents.
People should consider:
- whether they have a current Will;
- whether they have a contracting out agreement;
- whether the two documents work together;
- whether asset ownership has changed;
- whether there are children from previous relationships;
- whether trusts remain fit for purpose; and
- whether executors and trustees remain appropriate appointments.
Most importantly, people should ensure that each document reflects a cohesive succession strategy.
A broader lesson
The significance of Rimmer v Wilton extends well beyond the parties involved. The case demonstrates that estate planning is no longer simply about drafting a Will. Modern families have increasingly complex relationships, assets, and expectations. The most successful estate plans are those that integrate relationship property planning, Wills, trusts, business succession and beneficiary expectations into a unified plan, and, they are updated regularly.
Following the Supreme Court’s judgment delivered on 4 September 2026, please contact us to ensure that your existing estate plan involving a contracting out agreement remains suitable.
