A quarter of a million eligible voters are not enrolled, just 53 days away from the November 8 election.
Auckland Central electorate is the worst offender, with only 76 per cent of its 55,400 eligible voters enrolled. The national average is just above 92 per cent.
Not enrolling if eligible is a criminal offence carrying a fine of $100 for first offenders and $200 for each subsequent offence. No one was charged after the 2005 election.
Voting, however, is not a legal requirement. Just 80 per cent of enrolled voters voted in 2005.
Electoral Enrolment Centre national manager Murray Wicks said procrastination and a belief their votes didn't really matter were the main excuses offered by those not enrolled.
But the 2005 election was decided by just 50,000 votes - one-fifth of the number of those yet to enrol this year, he said.
Those eligible to vote must be at least 18 years old, be either New Zealand citizens or permanent residents, and lived in New Zealand continuously for at least one year.
There are disqualification rules too: anyone serving a prison sentence of more than three years loses their vote, as do permanent residents who have been out of the country for more than a year, or citizens who have been away more than three years.
Mr Wicks said enrolment officials were now circulating at the country's university campuses, high schools, rest homes and city streets.
Eligible voters could enrol by freetexting their name and address to 3676; going online at www.elections.org.nz; visiting a Post Shop or calling 0800 367 656. Those who wanted to check if they were properly enrolled could do so on the website, he said.
October 8 was the final day people could enrol if they wanted to cast a normal vote. Enrolling after that would mean they would have to cast a special vote, which would take them up to five times longer on election day.