The Electoral Commission says those standing in line at polling places will be able to vote even after 7pm.
Voting is open at more than 2300 places across the country.
But with people voting en masse, there have been reports of massive queues around the country.
A spokesperson said that additional staff were brought in to some voting places today because of high demand.
Between 11am and 2pm were usually the busiest times to vote on election day, they said.
Chief electoral officer Karl Le Quesne said people already standing in line would not be turned away.
"If you are waiting at your voting place to vote and it turns to 7pm, you can still stay on the line and cast your vote."
About 1.376 million have voted prior to Election Day; 3.5 million people are enrolled to vote.
In Auckland, some voters were reported to have queued up to 45 minutes before the booths even opened.
However, some polling booths in Cambridge and Kerikeri have been freeflowing today.
Le Quesne recommended people gave themselves a couple of choices on where to go to vote.
"We've seen quite a lot of people going to shopping malls and supermarkets, but sometimes ... the community hall or church hall can be pretty busy as well."
Le Quesne said this was people's last chance to go out and have their say on who they wanted to represent them.
There were also IT difficulties with the electronic version of the electoral roll, however, that has now been fixed.
The spokesperson said the app was used to look up people who did not have their EasyVote card or did not know which electorate they were in.
They said the issue has had no impact on most people's voting experience but caused some delays for people casting a special vote at some busier polling booths.
However, a voter in Wellington Central said today's voting was the worst voting experiences she has ever had.
IT difficulties with the electronic version of the electoral roll caused delays for those casting special votes.
"Probably the worst experience ever expected almost all the years I've voted," she said.
"It's got to be the most unorganized and shambolic experience I've ever had.
The voter who voted at Kelburn Primary School was in the booth's electorate, but did not have an EasyVote card.
She said she could not believe they were not able to just check people off on the paper roll like in years gone by.
She said some people left before voting because of the delays.
Weather was also affecting voting, with some locations closed.
The Adventure Bike Park at Cracroft, Banks Peninsula, was closed due to high winds, which meant voting was closed there, too.
Alternative voting places to the Bike Park are Te Hāpua Halswell Centre, Thorrington School Hall, Somerfield School Hall, and Pioneer Recreation and Sport Centre.
Tihiraki North Loburn School is currently closed due to fallen trees and flooding from a broken water tank. The nearest alternative voting place is Loburn School Te Kura Aromauka.
RNZ
