There were tears as Prime Minister Jacinda Ardern told delegates at the United Nations about a question she was asked by a young boy following the March 15 terror attack.

Addressing the UN General Assembly on Wednesday (NZ time), Ardern spoke about her visit to the Kilbirnie Mosque in Wellington just days after the Christchurch shootings.

She said a young boy gestured to her while she was there.

"He was shy, almost retreating towards a barrier, but he also had something he clearly wanted to say. I quickly crouched down next to him," the Prime Minister said.

"He didn't say his name or even say hello, he simply whispered: 'Will I be safe now?'"

Newshub asked the Prime Minister how she responded to the boy's question.

"I said yes," Ardern replied. "There are things that we could do in the immediate aftermath of the terrorist attack in Christchurch, and those things we did."

Ardern said the point she felt she needed to make was that the "sense of safety that a young child might feel or not feel, that's something that extends to all of us - not just within New Zealand".

The Prime Minister began her speech by reminiscing with the world about simpler times - when New Zealand was synonymous with sheep.

"There are things that we in New Zealand are well known for: Green rolling hills, perfect you might say for hobbits to hide and for plenty of sheep to roam."

But the murder of 51 people changed everything, she said, including how the world sees us.

"And now we are known for something else."

One woman from Sri Lanka left the chamber in tears as the Prime Minister told the United Nations General Assembly about the attack.

The Prime Minister has had a packed week in New York, including a one-on-one audience with US President Donald Trump on Tuesday (NZ time).

Ardern may have got the thumbs up from the President, but she also included a thinly veiled dig at Trump in her speech, arguing against fierce nationalism and self-interest.

It was in stark contrast to Trump's key message to the UN: America First.

"The future does not below to globalists; the future belongs to patriots," Trump told the UN General Assembly. 

He also failed to mention climate change - a focus of Ardern's speech.

"Places like Tuvalu, with a population of just over 11,000 people, barely contributes to global emissions but is paying the price for our collective inaction," Ardern said.

"Or Tokelau, a beautiful set of three atolls that can only be accessed by boat, where the children speak knowledgeably about climate change, knowing that unlike all of the challenges their self-reliant forbears have ever faced, this is one that is completely and utterly in other people's hands.

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"I can tell you that their expectations on us all are high."

It was during Ardern's trip to Tokelau earlier this year that National leader Simon Bridges rolled out his "part-time Prime Minister" attack line.

Now he's again attacking her international image versus her substance at home.

"It's a big game on the world stage; back home it's a mess and actually the reality isn't the same as the rhetoric offshore," Bridges told The AM Show.

But internationally, 'Brand Ardern' is as big as ever.

A CBS News promo said, "A deadly terrorist attack rocked her nation, her response got the world's attention: Jacinda Ardern."

She's holding the world's attention, but in a world that - after March 15 - now sees us very differently.