Jacinda Ardern meets Bill, Melinda Gates during New York trip

Prime Minister Jacinda Ardern has met Microsoft founder Bill Gates during her trip to New York.

Ardern met Gates and his wife Melinda during a visit to the Bill and Melinda Gates Foundation's Goal Keepers Summit, where she gave a presentation on how she believes a focus on wellbeing can reduce inequality.

The Prime Minister told those attending the summit she was well aware of inequality in New Zealand, which she put down to reforms in the '80s and '90s.

"I was young when this was happening, but I still remember it," she said.

"I was the daughter of a policeman in a town of 3000 people. I only had to look around me to see the people being left behind.

"If it's possible to begin building your social conscience when you are a small child, then that is what happened to me."

Ardern also mentioned the Government's wellbeing budget, which she said will move the country away from measuring success by economic growth.

"It took an evidence-based approach and focused investments in areas like child poverty reduction, helping homeless people off the streets and into supported living, sexual and family violence services and delivering on the aspirations of Māori, our indigenous people," she said.

"The centrepiece of the Wellbeing Budget was the largest ever investment in mental health services New Zealand has ever seen, including the development of a new frontline service where people can get support for mental health needs at their doctor in the same way they would for a physical ailment."

It's been a busy week for Ardern, who will return home from 10 days overseas on Saturday. She arrived in New York on Monday and has met Donald Trump, Boris Johnson and several other world leaders while there.

Ardern has also presented multiple speeches while in the US, including two to the UN, one at its Climate Action Summit and another at the General Assembly. 

She spent just under a week in Japan before arriving in New York, meeting Japanese Prime Minister Shinzo Abe and celebrating the start of the Rugby World Cup.