'I am Prime Minister - I have a job to do': Jacinda Ardern defends separate Nauru flight

Prime Minister Jacinda Ardern has defended her decision to travel separately to Nauru for the Pacific Islands Forum so she could spend more time with baby Neve.

Neve is too young to receive the vaccinations she needs to travel with the Prime Minister.

The Royal New Zealand Air Force jet flew back from Narau to pick up Ms Ardern, at a cost of possibly $100,000 - though Finance Minister Grant Robertson says money for the flight had already been allocated, and the pilots need to clock up flying hours.

"I was damned if I did and damned if I didn't," Ms Ardern said from Nauru on Wednesday.

"I did weigh up the issue, seriously looked at all of my options. That included whether or not I could hitch a ride with Australia over to the forum.

"At the end of the day, I am Prime Minister - I have a job to do. I felt it was important I be here alongside the Foreign Minister for this meeting.

"If I wasn't, outside of an election cycle, I would be the first Prime Minister since 1971 not to attend, and that didn't sit well with me."

Ms Ardern would be the first New Zealand Prime Minister to miss out on the forum in decades, but she wouldn't be the first Pacific leader - Australia's new Prime Minister Scott Morrison isn't attending the forum this year. Mr Morrison became Prime Minister after Malcolm Turnbull's leadership of the Liberal Party was challenged in August 2018.

Ms Ardern's decision to fly separately has attracted debate over the cost to taxpayers, and was picked up by international media

Some have said it's simply the cost of running a Government, while others have argued she need not have attended the event.

The AM Show host Duncan Garner said Ms Ardern should have let Deputy Prime Minister Winston Peters go in her place.

"I'm loathe to criticise a parent for wanting to be with their newborn. Been there, done that, understand it totally. But just pull out of the meeting," he said on Tuesday.

The AM Show news presenter Nadine Higgins said it's a temporary compromise.

"That child is currently breastfeeding but she won't be for that long, so these extra things that need to happen just at the minute won't last for long.

"I just don't think it's something we need to tie ourselves in knots over."