Two months out from the November 26 election, nearly 200,000 people aged between 18 and 30 are not enrolled to vote.
More than 120,000 people aged between 18 and 24 are yet to enrol, a shortfall of more than 70 per cent of the estimated 438,300 who should be.
In the next age bracket, 25-29, about 57,000 of the eligible 281,700 still need to enrol.
While it is not compulsory to vote, people aged over 18 are legally requires to enrol if they are a New Zealand citizen, or if they have permanent residency and have lived in the country for one year at some point.
Electoral Enrolment Centre national manager Murray Wicks said officials were working to improve young people's enrolment and would be at community events, shopping centres, and going door to door over the next few weeks.