Labour leader Jacinda Ardern was one of the first New Zealanders to vote in the 2020 election this morning – casting her ballot just hours after early voting began.

Her vote was "two ticks Labour," she told reporters who were invited along to witness the Prime Minister cast her vote.

She was joined by her fiancé Clarke Gayford, who also voted for Labour and Ardern - she is the local candidate in Mt Albert.

"He didn't get a choice," Ardern joked as the pair left the voting station.

She arrived with Gayford just after 11am and spent about two minuets in the voting booth.

There were only a few other voters at the centre this morning - two who passed Ardern on their way out both said they had voted for her.

"Oh, thank you," she replied.

Although she said he had voted for Labour, she did not reveal how she voted in both the referendums.

She will now speak at Labour's Get Out The Vote event, where she encouraged people to cast their ballot early.

Early voting officially opens across the country today and the take-up is expected to be higher than ever.

The Electoral Commission's Chief Electoral Officer Alicia Wright has said early voting could make up 60 per cent of the total overall number of votes. In 2017, early voting was 47 per cent.

The commission has been encouraging people to get out early and vote. The last day of the voting period is October 17.

Covid-19 significantly changed the plans for the election, which was initially scheduled for September 19.

The election results will be made known as they come through on the night of October 17.

But the initial results of the end of life choice and the cannabis referendum won't be known until October 30 – and the full results will not be confirmed until November 6.