Indigenous representatives from 123 countries are gathering for their 17th annual forum.
Dr Lance O'Sullivan, a Maori doctor and former New Zealander of the year, and 12 young people have been brought to New York by Kaitaia's Te Moko Foundation.
The trip, put together in three to four weeks, was funded by the generosity of New Zealanders.
"Some of those private individuals and donors don't look and sound like these kids and don't come from the same part of the country - young people do and that's inspiring to me," Dr O'Sullivan said.
The group is presenting on issues ranging from health, education, constitutional reform and the environment.
Dr O'Sullivan, who practices in Kaitaia, has transformed healthcare for Maori by cutting through bureaucracy - something the UN has struggled with.
"Process for process' sake is a killer - and we do need to break down the bureaucracy which slows up an organisation like this, but also what we see back home in New Zealand," he said.
The forum is also expected to be a learning experience for the young people.
"They've recognised being indigenous New Zealanders is part of a very wide and global community and I think it's been of huge value - recognising that they are in a family of First Nations people," Dr O'Sullivan said.