No call from Trump yet, but Ardern's not holding her breath

Jacinda Ardern isn't expecting a call from US President Donald Trump after becoming New Zealand's youngest leader in 150 years.

Ms Ardern last night found out she was Prime Minister-elect the same time as the rest of the country, when NZ First leader Winston Peters revealed after 7pm his party would be siding with Labour, ending National's nine-year run.

"I found out at the time all New Zealanders found out. I feel like we had a joint experience together," Ms Ardern told The AM Show on Friday morning, less than 12 hours after being crowned by the queen-maker.

"I did pick up a few hints in the speech before the final announcement was made, but it was fair to say it was a knife-edge negotiation.

"I absolutely believe it was a difficult decision for NZ First, and I thank them for seeing the common ground that we share and allowing me the privilege and the honour of leading the future Government."

The phone's been running hot overnight, with congratulations coming from Australian Prime Minister Malcolm Turnbull and Labor leader Bill Shorten, Canadian Prime Minister Justin Trudeau and the UK's Theresa May.

There's one particular major world leader she's yet to hear from - Mr Trump - but she's not waiting by the phone.

"I don't know whether or not there's any expectation that you hear from everybody, so I'm certainly not setting that bar," Ms Ardern said.

She said nobody "would be under any illusion around our difference in politics", but wouldn't let that get in the way of maintaining good relations with the superpower.

"My job is to further New Zealand's interests, and that's what I'll be doing no matter who is in charge."

She reiterated New Zealand would not send troops into North Korea just because Mr Trump asked, preferring a "multilateral" solution to world problems through the United Nations.