In 2008, a 28-year-old Jacinda Ardern stood in New Zealand's Parliament for her maiden speech.

The youngest-ever MP had already been a member of the Labour Party since age 17 and had spent time working in New Zealand and for former UK Prime Minister Tony Blair.
"Maiden speeches are a bit like words spoken in a heated argument - like it or not, they will come back to haunt you," she said.

"So today I want to share with you the words that I wish to haunt me, my values and beliefs, the things that brought me here. And I do so in the belief that should I ever abandon them, I will have the good grace to leave."

Just under 10 years later, the 37-year-old has been declared New Zealand's third female Prime Minister after a meteoric rise in a party she has been leading for just two and a half months.

Advertisement

Ardern says she felt an overwhelming sense of being "honoured and privileged" after a coalition with New Zealand First leader Winston Peters saw her take the top job over National Leader Bill English.

The young leader swept to power on a wave of "Jacindamania" after colleagues convinced her to take the leadership to revive Labour's struggling fortunes under previous leader Andrew Little.

In just seven weeks, she managed to bring Labour's share of the vote to 37 per cent, picking up more than 350,000 votes than the party did in the last election.

The whisky-loving former small-town girl was raised in Morrinsville and Murupara in a Mormon household where her father was a police officer. She left the religion in her 20s because of its stance on homosexuality and now considers herself agnostic.

She has previously said she likes drum 'n' bass music and loved metalwork and history at school. She joined the Labour Party at 17 and worked for former Labour leader Helen Clark before moving to London to work for Tony Blair's office.

Ardern's relaxed style and easy smile saw her gain popularity during the campaign, and she won support for saying it was "totally unacceptable" to ask women about plans for a family after just six hours in the job.

She lives in Auckland with her partner, broadcaster Clarke Gayford. Her politics has been focused around key issues of immigration, housing, cost of living, climate change and student debt - with one of her first policies to build a light rail from Auckland airport to the CBD funded by a fuel levy.

She is likely to have an awkward first encounter with Foreign Minister Julie Bishop, who accused New Zealand's opposition Labour Party of conspiring to undermine her government after questions were raised about Deputy Prime Minister Barnaby Joyce's Kiwi citizenship in the New Zealand Parliament.

The front page of The Australian today.
The front page of The Australian today.

"This is highly unethical, at least, but more importantly, it puts at risk the relationship between the Australian Government and the New Zealand Government," Bishop said at the time.

"Should there be a change of government, I would find it very hard to build trust with those involved in allegations designed to undermine the Government of Australia."

Ardern responded at the time the claims were false and "highly regrettable". She said she had contacted the Australian High Commission to register her disappointment and would be meeting the commissioner in person.

A writer for the Sydney Morning Herald called the decision 'NZ's Brexit'.
A writer for the Sydney Morning Herald called the decision 'NZ's Brexit'.

Since the result, Australian Prime Minister Malcolm Turnbull has congratulated the young leader, as has Bishop who said claims she targeted Ardern were "rubbish".

"Rubbish. Read what I actually said. I agree entirely with Ms Ardern's admonishment of her colleague - that his conduct was 'unacceptable'", she tweeted on Thursday.

Following the result, Ardern reaffirmed her commitment that "Labour believes in a government that looks after its environment, and that looks after its people."

"I want to thank all those who gave Labour support throughout the election and period of negotiation."

"We take very seriously the responsibility we have."

NZ First leader Winston Peters said the Greens had a confidence and supply agreement with Labour - outside the Government - while NZ First had the full coalition, including roles inside Cabinet.

Ardern says NZ First will hold four Cabinet positions and one parliamentary undersecretary. Peters has been offered the deputy PM job.