Labour leader Jacinda Ardern says that she would not have been prepared to have embattled Green Party co-leader Metiria Turei in the Cabinet.

Photo: RNZ / Chris Bramwell

Mrs Turei has ruled herself out of ministerial positions if Labour and the Greens win this year's election, following revelations that she lied to Work and Income in the 1990s and that she had enrolled to vote at an address where she was not living, in 1993.

At a media conference announcing the Labour Party's new slogan and its campaign approach to the election, Ms Ardern said she would not have been prepared to have Mrs Turei as a minister anyway.

She said it was a "sad set of circumstances".

"[Metiria Turei's] reflected on the issue herself, and has come to the conclusion herself that it would have been untenable, I think she made the right decision."

Ms Ardern said she told the Green Party her view this morning, but would not be drawn into whether it could have had an impact on Metiria Turei's decision.

"It's about setting a standard, but actually it was also about respect. It was only fair that I convey to the Greens my personal view."

Ms Ardern said the Memorandum of Understanding between the two parties still stands.

The Labour Party ditched its campaign slogan and billboards after Ms Ardern replaced Andrew Little as its leader, with Kelvin Davis taking the position of deputy leader.

'Let's Do This' replaces 'A Fresh Approach' as the party's new slogan.

When she was announced as leader Ms Ardern said she would take 72 hours to take stock of the campaign.

"And, as I said at the beginning, Labour's core focus was the right one. Housing, health and education didn't come from nowhere. They came from voters, they came from the public. That's why these ideas will continue to be our focus."

Ms Ardern said in the near future there would be additional policy announced in the areas of housing, education, key infrastructure and the environment and there would be announcements with a Māori focus.

Ms Ardern will stage a new policy launch in Auckland on Sunday.

She said the 'Let's do this' tagline came about almost inadvertently.

"When I first wrote a post on social media about the campaign I finished it with the most natural conclusion - let's do this. It's not just about the next seven weeks, it's what we can do if we're in a position to make change. I'm excited by this campaign, and by what's possible."

Earlier today, Jacinda Ardern explicitly ruled out any post-election deal that would allow Winston Peters to be Prime Minister.

Ms Ardern told Nine to Noon that wasn't an option saying "I'm happy to rule that out now".