Prime Minister Jacinda Ardern had a brief encounter with US President Donald Trump last night in which he congratulated her on baby Neve and she responded by raising trade tariffs with him — as well as acknowledging his contribution on the Korean Peninsula.

Ardern and partner Clarke Gayford attended a reception hosted by Trump for about 140 leaders in New York for the UN General Assembly.

Afterward, a spokesman for Ardern said they had a chance for a brief chat before a photo of the pair was taken.

He had congratulated her on the birth of Neve, and Ardern had "acknowledged" the President's work with Kim Jong-un in attempting to denuclearise the Korean Peninsula.


"The Prime Minister also used the opportunity to promote the ongoing work of NZ and US officials on the lifting of steel and aluminium tariffs."

In the lead up to the General Assembly, Ardern had said she would not seek Trump out for a chat but nor would she try to avoid him. She had said if she did have a talk with him, her top topic would be trade because of its importance to him.

Unlike Australia, New Zealand has not secured an exemption from the tariffs on steel and aluminium the Trump administration is imposing.

This morning Trump delivered his statement to the UN General Assembly which included a warning that there was no reprieve on the horizon when it came to his stance on trade.

"We believe trade must be fair and reciprocal."

He sad the US had opened up its economy too much, and other countries had taken advantage of that to "dump" goods.

He issued a diatribe against the rules of the World Trade Organization system which New Zealand relies on, saying the worldwide trading system was in need of major reform because countries could "rig the system" in their favour.

Trump has withdrawn from multilateral deals, including the Trans Pacific Partnership, saying he preferred one-on-one deals with individual countries.


He pointed to recent deals signed with Mexico and, this week, Korea, saying these were just the beginning.

China is the primary target of the tariffs so far, and he said there were now $250 billion worth of tariffs imposed. China has retaliated in kind — and US consumers are about to feel the pinch of more expensive goods from cycles to vacuum cleaners.

Ardern's day began with an interview with CNN's Christiane Amanpour.

The presence of baby Neve in the General Assembly yesterday also continued to garner attention — from Fox News to Vogue.

The New York Times listed Ardern as one of the "leaders to watch".

Vogue's article said Ardern had become something of a "feminist hero" and said taking her baby to the General Assembly was remarkable:

"Ardern is a woman with a new baby and an important job, and she didn't feel the need to hide that fact in order to assert herself on the world stage. That's a notable departure especially for American audiences ...

"From all of us who have pumped breast milk on a work trip and transported it back home on an airplane, or conducted a conference call with a baby on her lap: Jacinda, we salute you."

Ardern's meetings today include new Spanish President and UN Goodwill Ambassador, actress Anne Hathaway. Hathaway is also a mother and advocates for paid parental leave.