The Electoral Enrolment Centre has kicked off a campaign to try get the one in four unregistered young voters to sign up.
The campaign includes using social network Bebo and a dedicated youth enrolment week.
There were 108,600 18 to 24-year-olds eligible to enrol who have not.
EECmanager Murray Wicks said the number was about the same as the total number of eligible voters in Hamilton or all eligible voters in Rotorua, Gisborne and Nelson combined.
The campaign involved musicians, actors, community groups, organisations and individuals promoting the message it was easy to enrol and voting was easy and relevant.
Youth enrolment week would run from August 11.
"We want to tap into the networks of young people across the country to get them enrolled," Mr Wicks said.
"This means reaching them online through communities such as Bebo, on the ground where they are studying or taking time out and also in the community and through their families and other networks."
A competition was being run on Bebo to get young people to make their own ad about enrolling and voting.
Students at Auckland's AXIS Adschool produced a series of viral advertisements to kick-start the Bebo campaign.
There were 302,000, or almost 75 per cent, of 18 to 24-year-olds enrolled.
