People who have moved house and not updated their address with the Electoral Commission may not be able to vote at next month's general election.
Chief Electoral Officer Alicia Wright says 60,000 enrolment update packs - confirming your address and electorate you can vote in - were returned in July, marked "gone, no address".
This might only represent 0.02 percent of the enrolled voters in New Zealand but it's a still a sizeable chunk of people that can make a difference on election day, Ms Wright said.
The number is about the same as at the last election in 2014, she said.
Voters whose packs are returned to sender are taken off the electoral roll.
It is easy to update enrolment details online at elections.org.nz, by filling out a form at a PostShop, or requesting one by calling 0800 36 76 56 or texting 3676.
Enrolments can occur right up until midnight on September 22, the day before the election.
Advance voting starts on September 11.