"Ultimately, we can provide all of that, but unless there is a culture that accepts that children are part of our workplaces, then we won't change anything," she said.
"If I can do one thing and that is change the way we think about these things, then I will be pleased we have achieved something."
Ardern said she was lucky to be the second leader in the world to have a child while in office.
"I have an incredible support network around me and I have the ability to take my child to work. There's not many places you can do that."
Ardern's week in New York, along with about 140 other leaders in town for the UN General Assembly, will include appearances on major US television shows, a meeting with actor Anne Hathaway, and her first speech as NZ leader at the United Nations.
The Prime Minister is travelling with her partner Clarke Gayford and baby Neve, who was briefly glimpsed with her father at the United Nations. Gayford is tagging after Ardern where possible so Neve can be fed.
A tweet from Gayford revealed Neve had kept her parents up until 3.30am after they landed after midnight.
Ardern said baby Neve was "probably more rested than I am."
Asked how she had recovered, Ardern laughed and said "I'm not sure I have," before adding "with the support of others".
