The Electoral Commission mailed enrolment update packs to everyone on the electoral roll at the end of June, asking them to check their enrolment details.
The Wellington Central electorate had the most voters removed from the roll with 1237, while the Waimakariri electorate had the least with 351.
Enrolment services national manager Murray Wicks said voters who had moved house and not updated their details needed to complete a new enrolment form.
"If you didn't get an enrolment update pack, we don't have your correct enrolment details. You need to enrol now so you can have your say in the September 20 general election," he said.
People can check their enrolment online at www.elections.org.nz, by calling 0800 36 76 56, or by checking the electoral rolls at PostShops and public libraries.
Voters can freetext their name and address to 3676, get a form from a PostShop or call Freephone 0800 36 76 56. People can enrol or update details at elections.org.nz.