UPDATED 12.25PM: New Labour Party leader Jacinda Ardern has promised ‘relentless positivity and a clear vision' in her party's campaign to change the government.

She made the statement at a press conference early this afternoon, flanked by deputy Kelvin Davis and other Labour MPs.

She began by giving thanks to her predecessor Andrew Little.

'His announcement and our situation is not what anyone expected or wanted. He is first and foremost loyal to Labour. I thank him for his support and incredible work – a sentiment expressed to him by caucus also.

'The circumstances may not be what Labour has planned for this election, but it has not weakened my resolve or focus.”

She says her and Kelvin's nominations were unanimously accepted by their colleagues.

'I find myself incredibly lucky to call myself leader, and to work alongside someone as committed and talented as Kelvin.”

She says the party has ‘huge aspirations' for New Zealand.

'Yes, we are an optimistic nation. But when you work at the coalface of politics and communities we do, we see every day we can do better than this. We can be better than this. At stake is a chance to build a New Zealand better than we found it, and a future to look forward to.”

She plans to take the next 72 hours to ‘take stock of the campaign plan' and make any ‘additional policy announcements'.

'I'm privileged and honoured to be the leader of the Labour Party,” says Jacinda.

'We will be positive, organised, and ready. I absolutely believe I'm up for the job.”

Maori Party president Tukoroirangi Morgan has asked the new Labour Party leaders to work with them ‘in the best interests of Aotearoa'.

"Maori people throughout the country are telling me they want our party to work with Labour if it's in a position to form a government after September 23,” he says.

"We've always said we'd work with both sides, blue and red, but Andrew Little killed off any hope of that happening when he closed the door on us.

"We're hoping Jacinda and Kelvin won't be as closed minded and that they'll agree to work with kaupapa Maori.”

However, Labour's new leader says they intend to ‘take all' of the Maori seats, while her deputy has expressed scepticism of working with the minority party.

'If the Maori Party are still standing after the election, they will have to up their game to work with us,” says Kelvin.

EARLIER:

Andrew Little's former deputy Jacinda Ardern has been endorsed by her colleagues as the 17th leader of the New Zealand Labour Party.

The announcement was made after the party's caucus meeting today, following Andrew's resignation at a press conference this morning.

Her deputy will be Te Tai Tokerau MP Kelvin Davis.

Jacinda is only the second woman to lead the party after Helen Clark, who was the longest-serving Labour Party leader, and also the first Labour prime minister to win a third term.

At 37 years old, Jacinda is also the party's youngest leader since it's inception in 1916.

She consistently ranked higher than Andrew as preferred prime minister in several political polls leading up to today's announcement.

If Labour is able to form a government and Jacinda becomes prime minister after September 23, she will be the second-youngest PM in the country's history, after 19th-century politician Edward Stafford.