Jacinda Ardern opens up about Nauru flight backlash in New York Times profile

Prime Minister Jacinda Ardern has revealed how being criticised for taking an extra flight to a Nauru forum took an emotional toll on her.

In an in-depth interview with The New York Times, Ms Ardern spoke about how being a breastfeeding mother of a baby too young to have all the necessary vaccinations meant she faced a 'damned if I did, damned if I didn't' decision.

Determined to attend the important Pacific Islands Forum (had she not gone, she would have been the first Prime Minister not to do so outside of an election cycle since 1971), the Royal New Zealand Air Force jet made an extra trip back from Nauru to pick her up.

The flight would have cost about $100,000, but Finance Minister Grant Robertson said that money had already been allocated, so there was no additional cost to taxpayers.

Her decision to miss the forum's opening ceremony in order to spend less time away from Neve dominated news headlines this week, with many saying she should either have stayed the full three days or let Winston Peters go in her place.

Ms Ardern told The New York Times that the intense scrutiny hit her unexpectedly hard.

"What surprised me the most is how hard I took that, being given a hard time for going - but actually it did upset me a bit."

She said Kiwis are extremely opposed to their taxes being used to fund unnecessary expenses for politicians - Simon Bridges' $113,000 roadshow is a timely example.

"In New Zealand, we're really careful about excess," she said.

"I hate the idea of anyone thinking that I don't put a lot of thought about the cost to taxpayers. I make our ministers travel to events in vans to pool together."

The article mentioned the Prime Minister's decision to freeze all MPs' salaries and allowances for a year, and stopping a 3 percent pay rise in favour of a "fairer formula".

Ms Ardern also discussed being the second world leader to give birth and the first to take maternity leave, saying she wants to be "a good leader, not a good lady leader".

"I don't want to be known simply as the woman who gave birth."

She mentioned receiving a letter from a young woman who said her own boss was more understanding about her pregnancy because of Ms Ardern's very public example.

"He saw this expectation being built around making sure that women could have babies and remain in their jobs," she explained.

"And I thought, well, even if I only create that sentiment or that environment or even create a little bit of solidarity for other women, that is something."

The New York Times also asked her about US President Donald Trump, who she'll spend time with later in September when the United Nations meets for its General Assembly in New York.

When asked if she was worried that President Trump might give her an insulting nickname - as he has done for the likes of Hillary Clinton, Joe Biden and Elizabeth Warren - she didn't seem concerned.

"I've been given so many, it'd be quite hard to come up with a new one," she said.

"Back in the early days of my political career, I was called Socialist Cindy. I just hate the nickname Cindy."