With an average of one New Zealander being deported from Australia every day, Prime Minister Malcolm Turnbull might find the reception across the Tasman a tad cooler than usual when he arrives in Auckland tonight.

The New Zealand government is delighted to be hosting the Prime Minister on his first overseas trip and the leaders of the two most integrated economies on earth share a lot of common ground.

And Mr Turnbull can learn a lot from his mildly centre-right counterpart.

John Key is in his seventh year as prime minister and has increased his majority at every election, while Australia has churned through five leaders and two governments.

He has succeeded in the face of the Christchurch earthquake and a recession after the global financial crisis, all while making tough calls like increasing the Goods and Services Tax.

He also turned the reintroduction of Knights and Dames into a winner and posted a Budget surplus this week.

But when the hard talk begins, at the top of Mr Key's agenda will be the 160 New Zealanders deported this year, the 196 in immigration detention and the up to 1,000 others that might soon be sent packing.

It is an issue that has galvanised New Zealand and is regularly leading the news there.

Deportations spiked after a change to the Migration Act late last year. It lowered the threshold for visa revocation from someone with a "substantial criminal record" to anyone who had served a prison term of a year or more.

There are over 600,000 New Zealand citizens, who are Australian residents and many have lived here most of their lives.

They are less likely than average to be jailed but, at any time, there are about 1,000 in the prison system.

While it might be hard to garner much sympathy for people with criminal records, there have been some disturbing deportation cases which have helped to turn public opinion in New Zealand against Australia.

Like Junior Togatuki, who arrived when he was two and who had three siblings who were born here.

He did have a serious criminal record but the 23-year-old was due to be released from Goulburn jail when his visa was revoked.

A month after his sentence expired, he was still being held in isolation in Supermax. That is where he died in September, his wrists slashed with a prison-issue razor blade.

Turnbull 'a sensitive guy', Key says

Mr Key said this week that the policy did not take into account a person's "community of interest".

He has already raised the large number of deportations with the Foreign Minister and former prime minister Tony Abbott.

His conversation this weekend with Mr Turnbull would be "extremely direct".

"We think the policy is set at the wrong place," Mr Key said.

"We don't think it's fitting with the overall relationship we have, and we think there is a strong case for a special carve out for New Zealand, at least in the way the threshold is set. And I don't think that's unreasonable."

There seems to be a sense in the New Zealand media, and perhaps its government, that Mr Turnbull might take a softer view on this than his predecessor.

Mr Key noted during a long press conference on deportations that he thought Mr Turnbull was "a sensitive guy".

As he heads to Auckland, Mr Turnbull looks set to be caught between the rock of Mr Key and the very hard place of his colleagues.

Being seen to back down on any aspect of border protection will only confirm the worst fears of the conservatives.

Once that — not inconsiderable hurdle — has been cleared there are much happier pastures for both prime ministers.