Labour leader Jacinda Ardern is sticking with the party's immigration policy, and wants to reduce the number of new immigrants coming into New Zealand each year by tens of thousands.

A record number of 72,000 new immigrants settled in New Zealand last year, contributing to a record increase in the country's population, which economists claim is putting stress on the New Zealand's infrastructure.

In April, former leader Andrew Little said a Labour government would cut immigration by tens of thousands a year.

Ms Ardern confirmed to Morning Report today that the party was committed to that policy.

She said Labour saw it as an infrastructure issue.

"New Zealand has been built off the back of support from those who have migrated to New Zealand and made it their home, and that will continue to be the case. Our concern is that there hasn't been enough planning about population growth, we haven't necessarily targeted our skill shortages properly, and that means Auckland has borne the brunt of a lot of that growth."

She said she was not fixated on numbers, but a drop of 20,000-30,000 was "still the estimate we have".

Ms Ardern said it would have an impact on the education sector, but Labour did not think it would take a "massive hit".

Watch the full video of Ms Ardern's interview with Morning Report - including more on Labour's connection to the latest dual citizenship issues for an Australian politician - here: