Can a will be challenged if the person wasn't of sound mind?
Common question · Contested Wills & Estates · New Zealand · 23 October 2026
General information from Lawmateanz
Yes. In New Zealand, a will may be invalid if the person didn't have 'testamentary capacity' when they made it. That means they didn't understand they were making a will, what they owned, who might expect to benefit, or the effect of what they were doing.
A will may also be challenged if it was made under undue influence, meaning someone pressured the person so the will didn't reflect their own wishes, or if it wasn't properly signed and witnessed.
Evidence matters. Medical records from around the time, the lawyer's notes from when the will was made, and witnesses can all be important.
If a will is found to be invalid, an earlier valid will applies. If there isn't one, the estate is shared under the intestacy rules.
These cases can be complex and costly, so get advice early. Community Law Centres and estates lawyers can help.
Written by Lawmateanz, not by a lawyer. General information only, not legal advice about your situation. For advice about your own matter, talk to a lawyer.
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