"We are a party who was at the same time campaigning to double our refugee quota. We are a nation built on immigration.
"I am only a third-generation New Zealander. The suggestion in any way that New Zealand wasn't an open, outward-facing country … made me extremely angry."
McFadden made a different comparison, saying Ardern was similar to US Presidential candidate Bernie Sanders because of her socialist background. Her coalition with NZ First leader Winston Peters was like Sanders teaming up with conservative Republican Ted Cruz, she said.
The interview focused primarily on Ardern's status as just the second woman head of state to give birth while in power.
"I'm looking forward to the day when we won't have news stories about that because it won't be nearly as unusual," Ardern said.
"But for now I accept that that's just the way it is."
McFadden also raised a Daily Mail column which said a pregnant Prime Minister "was not feminism" but a betrayal of her voters.
"Eh," Ardern replied. "Women multitask every single day. Every single day. The sentiment in that piece suggests that women can only be mothers or other. Can I be a Prime Minister and a mother? Absolutely. Absolutely.
"Will I have help to do that? Yes."
Responding to the broadcast this morning, Act Party leader David Seymour accused Ardern of rewriting history by saying her campaign had been outward-facing.
Labour had promised to cut migrant numbers by up to 30,000 and since coming to power had restricted foreign investment in property.
"The idea that Labour ran a campaign that was open to the world is completely false. It has now delivered on its promise and is running a xenophobic government."