Malcolm Turnbull has defended deporting New Zealand citizens as moral, even though the country's prime minister Jacinda Ardern says it makes no sense for someone who has never set foot in her country to be sent there.

Australia's policy of deporting people, including New Zealanders, who fail the character test in the Migration Act, was a point of tension during this morning's talks between the two leaders.

The approach has been fiercely debated between the two nations ever since Australia changed its law three years ago so that non-citizens can be deported for reasons including being sentenced to a year or more in prison.

New Zealand has been most affected by the migration law change because of the number of its citizens in Australia.

It has been deeply controversial in cases where New Zealand citizens have been in Australia for decades or since they were young children.

The most prominent recent case involves a man, Alex Viane, who was born in American Samoa and received New Zealand citizenship as a child but has never visited the nation.

Mr Turnbull was repeatedly asked by a New Zealand journalist this morning if sending back New Zealanders who had never been to NZ was moral thing to do.

"The answer to your question is yes," Mr Turnbull said, making it clear the policy would not change.

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But he emphasised New Zealanders who were to be sent from an Australian jail back across the Tasman had a right of appeal.

Mr Turnbull said the latest figures provided to both leaders this morning showed that just under 40 per cent of appeals had been successful.

"This is in accordance with Australian law, and the process is a fair and just one," he said.

"I absolutely accept that the Australian government is well within their rights to exercise their deportation policy as they have," Ms Ardern said.

"I have raised again, as we have on previous occasions, elements of the deportation policy where for instance someone has never stepped foot in New Zealand.

"We have been keen to make sure the Australian government is aware of our perspective on that and our strength of feeling, but ultimately it is in the Australian government's hands to determine how they manage that element of the policy."

Mr Turnbull said he was aware of the strength of feeling about the issue in New Zealand, but noted that the policy applies to all non-Australian citizens.

"It is our sovereign right to determine whether and in what circumstances non-citizens can remain within our borders and within yours in New Zealand," he said.

With Mr Turnbull refusing to budge on the policy, Ms Ardern was asked by a New Zealand journalist if her nation was "just being bullied".

Ms Ardern rejected that, saying Australia had made some concessions on the appeal process.

But she said she would keep arguing that people born in Australia should not be subject to deportation.

"What we are seeking is to put an end to some of those cases where, from our perspective, it makes no sense for someone who has never stepped foot in New Zealand to be deported here [to New Zealand]" Ms Ardern said.