Can you get a prenup after marriage
Updated 2026-08-09. General information, not legal advice.
Yes. In New Zealand you can sign a prenup after you are already married, in a civil union, or years into living together. Section 21 of the Property (Relationships) Act 1976 lets couples make a contracting out agreement before or during the relationship, so what other countries call a postnuptial agreement is, here, exactly the same instrument with a later signing date. The requirements are identical too: written, signed, independent legal advice for each partner, witnessing and certification.
The main difference is practical, not legal: by the time you are married or past three years together, property interests have usually already arisen, and the agreement has to deal with them honestly.
Why sign an agreement during a marriage?
Common triggers: an inheritance or family gift arrives and the family wants it ringfenced; one partner starts a business and both want the family home insulated from business risk; a trustis being settled and the structure needs the couple's property rules stated; parents are helping with a house deposit on the condition it stays protected; or a couple simply never got around to it before the wedding and still wants their own rules rather than the Act's default.
Blended families are the biggest category. Partners with children from previous relationships often sign mid-relationship agreements so that death does not force a choice between the new partner and the children.
What changes when property has already mixed?
After three years of marriage or de facto relationship, the Act's equal sharing rules generally already apply to your relationship property. An agreement signed now is not writing on a blank page: it is re-classifying interests your partner may already hold, which is precisely why the law demands independent advice. Expect your lawyers to be careful, to require full disclosure, and to flag anything that looks like one partner giving up significant existing rights for nothing.
That last point matters for durability: an agreement in which one partner surrenders established entitlements cheaply is the kind a court can later set aside for serious injustice. Mid-relationship agreements hold best when both partners get something real from the bargain.
Postnup, prenup or update, which do you need?
If you have no agreement, you are simply making a contracting out agreement now, whatever anyone calls it. If you signed one before the wedding and life has moved on, you are updating an existing agreement, which means a new certified agreement or formal variation. Either way the process is the same: agree the substance together, then separate lawyers, advice, witnessing and certification under section 21F.
Common questions
- Can you get a prenup after marriage in NZ?
- Yes. Section 21 agreements can be made before or during a marriage, civil union or de facto relationship. A postnup is the same contracting out agreement signed later, with the same validity requirements.
- Is a postnup weaker than a prenup?
- Not inherently. The legal requirements and effect are identical. Mid-relationship agreements attract closer scrutiny of fairness because existing entitlements are being re-classified, so full disclosure and genuinely balanced terms matter even more.
- We are past three years de facto. Is it too late?
- No. Equal sharing interests have generally arisen by then, but a contracting out agreement can still set your own rules going forward and deal with existing property, provided both partners understand and accept what they are agreeing to with independent advice.
Sources
All information published on prenup.nz, including this guide, is general information only and is not to be construed as legal advice. We strongly recommend seeking independent legal advice about your own situation. A contracting out agreement only binds you once each partner has taken independent legal advice and a lawyer has witnessed and certified each signature, as section 21F of the Property (Relationships) Act 1976 requires.