Describing the decision as "a step change in the relationship", Ardern also fired a broadside at Australian Prime Minister Anthony Albanese's predecessor, Scott Morrison.
Ardern has arrived in Sydney on her five-day visit as New South Wales contends with major flooding after days of torrential rain.
She said she will discuss the number of Kiwis affected by the flooding in New South Wales when she meets Albanese on Friday.
When asked whether she was surprised by the decision to avail flood relief to Kiwis, Ardern said it "was always my expectation that New Zealanders would have the same access".
"What stood out to me more was the fact that they [Kiwis] didn't. This for me feels like a natural return to a policy now grounded in fairness. What happened before was grossly unfair," Ardern said.
"I think it fundamentally represents a Government that takes a different view to Kiwis in Australia and the contribution they make.
"It's a sign of the contribution New Zealanders have long made to Australia."
Ardern said there were about 150,000 New Zealanders in New South Wales. Knowing there was equitable treatment showed they were increasingly valued.
Ardern said they saw "pretty much the opposite" treatment under the former Morrison government.
The PM said it was part of the "reset" in the relationship they were hoping for.
Ardern was speaking to media after a tourism meeting with Australian ministers and tourism sector business representatives.
Climate change was an area New Zealand and Albanese were "very keen" to work together on, she said.
On the leaders' forum tomorrow evening and mood of businesses with change in Australia's government, Ardern said businesses were looking at sustainability so that should be a focus.
On aviation collaboration, Ardern said Air New Zealand was working with Singapore Airlines on issues like biofuels.
This was important to avoid a race to the bottom, better for "people and planet". Qantas was looking to get involved in that too, Ardern said.
Increasingly consumers want to feel good about their travel, Ardern said.
Asked about the more than 10,000 new Community cases today, the highest daily mark since April, Ardern said advice was the most meaningful thing to make an impact was boosters, vaccinations and mask use.
Waitematā was responsible for a siginificant part of the increase and the high case numbers in hospital.
New waves were not unexpected and New Zealand had prepared for this, but Ardern said she acknowledged the toll it was taking on the workforce.
The rest of New Zealand needed to show solidarity with the health workforce by getting vaccinated and wearing masks, Ardern said.
This afternoon Ardern will head to David Jones for the launch of the Discover New campaign – a one-month campaign promoting New Zealand fashion, food and homewares brands, from Karen Walker and Deadly Ponies to Huski Coolers and Swanndri.
Her arrival in Sydney coincides with Australian authorities confirming a Disaster Recovery Payment scheme for New Zealanders living in the flood-affected zones of New South Wales – lump sum payments of $A1000 per adult and $400 for each child under 16.
Ardern will meet Albanese on Friday as he faces questions about the amount of time he has spent overseas since winning Australia's election in May.
Both he and Ardern were last week at the NATO summit together in Madrid and both will also go to the Pacific Islands Forum in Fiji next week.
Albanese is due to visit the flood-hit areas of New South Wales today ahead of the Australia-New Zealander leadership forum.
He defended the amount of time overseas, saying he was attending important events that were already scheduled prior to his election.
"We can't separate international events from the impact on Australia and Australians, and those people might like to say which of the events I've attended on behalf of Australia that I shouldn't have attended."
In Melbourne, Ardern also had to address domestic issues – defending the Government's approach to immigration after New Zealand's ANZ chief executive Antonia Watson urged the Government to make the country's immigration settings more "flexible" to help businesses struggling with staff shortages.
"I totally understand that we want a more productive country. That will take years and investment," Watson said.
"In the meantime … people are just crying out for staff."
Watson made the comments to media at an event hosted by ANZ in Melbourne on Tuesday morning, which was attended by Ardern, Tourism Minister Stuart Nash, and a 31-person strong business delegation from New Zealand.
"I understand there's the desire for a bit of a [immigration] reset, and in the long-term that could be a good thing for the country. We need to have planned better for the immigration we've had over the last few years," she said.
Ardern told media the Government isn't planning to loosen immigration settings.
"We have worked very hard to identify the skills gaps New Zealanders have; the issues businesses are facing; and actually, to ease the path for those businesses to bring in those skills that we need. We've made significant changes to do that," Ardern said.
"In other areas that perhaps might not be areas where we're seeking those high levels of skills; where it might be in industries that traditionally have had lower wages; we're trying to maintain the wages and standards we have in New Zealand.
"Because otherwise, we unfortunately do see wages decreasing, potentially as a result."
