Prime Minister Jacinda Ardern is slapping down the Opposition leader's idea to fight fire with fire on the issue of Australia deporting New Zealanders who commit crimes across the Tasman.

This morning National Party leader Simon Bridges said a National-led government would deport Australians convicted of serious crimes in New Zealand.

"It's the legal right of the Australian government to deport Kiwi criminals. However, we have the same rights and it's my view that New Zealand needs to explore how a reciprocal policy could work here," Bridges said.

"While Jacinda Ardern has labelled this issue as corrosive to our relationship with Australia, I don't agree. In principle, if it's right for Australia, it's worth exploring whether it's also the right position for New Zealand and our interests."

But Ardern shot down this proposal at her post-Cabinet press conference this afternoon, saying it was wrong in principle as well as in proportion.

"If we think this policy is wrong why would we then repeat it?" she said.

"We have roughly ... 62,000 Australians living in New Zealand. We have over 650,000 New Zealanders living in Australia.

"There is a question of proportion here and I think his position is naive."

New Zealand already had the ability to deport criminals from New Zealand back to their countries of citizenship, she added.

Ardern has continued to stress her opposition to Australia's deportation policy, which has been linked to the rise of rival gangs in Tauranga.

• National considers reciprocal deportations for convicted Australians

One of her main concerns is that New Zealanders are sent back to these shores even if they were not born here, or with little in the way of a support network or family here.

Ardern said she would continue to voice her concerns, including to her Australian counterpart Scott Morrison when they meet in Sydney later this week, even though her advocacy at the highest level has so far fallen on deaf ears.

"We must make the point that it is wrong. The best way I can continue to make that is not by replicating something that I don't agree with.

"Australia is within their rights to do what they're doing. It doesn't mean what they're doing is right.

"I don't think I should sit back and ignore that, simply because they haven't changed their mind to date. It continues to be a policy I fiercely disagree with. It's wrong and I'll continue to raise that."