Two senior New Zealand ministers have taken a brickbat to Australia, calling the politics of deportations "venal" and warning the issue is straining relations between the two countries.

Key points: In the past three years 1,300 Kiwis have been deported to New Zealand

In the past three years 1,300 Kiwis have been deported to New Zealand In the same time, New Zealand has sent back nine Australian citizens

In the same time, New Zealand has sent back nine Australian citizens Peter Dutton says the deportation is not in breach of human rights

The criticism comes in the wake of a steep rise in deportations of Kiwis since the passage of laws in 2014 that allowed deportation of long-term Australian residents, who are not citizens, on the grounds of "character", as well as those who have been sentenced to prison for 12 months or more.

"Many are being sent back here with no real connections, no real networks, no real support," New Zealand Justice Minister Andrew Little said.

"Look, it might suit Aussie politics, and it seems to me that there is a venal, political strain to all this.

"It's certainly not consistent with any humanitarian ideals that I thought both countries once shared."

Mr Little was referring to the case of Ko Haapu, who was living in Perth when the laws were passed with bipartisan support.

Ko Haapu was assigned to the personal security detail of then New Zealand prime minister John Key in 2010. ( Supplied )

The former New Zealand soldier was judged to be of good enough character to be assigned to the personal security detail of then New Zealand prime minister John Key when he visited Afghanistan in 2010.

Later, he was working as a scaffolder and in a relationship with a Perth woman and her daughter, whom he regarded as his own.

In his spare time, he became a member of the Rebels motorcycle gang — which, despite the gang's notoriety, is not against the law in WA.

After visiting a member of the gang in Casuarina prison, he was arrested — by his account, thrown to the ground by a group of officers, and spent that night in solitary confinement.

For five months, he was held in prison without charge and told he would be staying there until the long legal process took its course, or until such time as he agreed to sign the papers which would see him quickly deported to New Zealand.

When Mr Haapu did finally sign the papers, he found himself at Perth International Airport, in handcuffs and ankle bracelets — connected by a chain — being escorted onto an Auckland-bound plane by officers who stayed with him the whole way there, until they could be sure Australia was safely rid of him.

All this without charge.

Ko Haapu joined the Rebels motorcycle gang when he lived in Western Australia.

Immigration Minister Peter Dutton indicated the Federal Government knows more about Mr Haapu than they care to place in the public domain.

"There's intelligence that's gathered that's not released for a variety of reasons," Mr Dutton said.

"He was a member of the Rebels outlaw motorcycle gang and we know that they are part of a syndicate which is the biggest distributor of drugs in our country. If you're a member of that gang, you face deportation.

"Families who have had kids die of overdoses, because of drugs given [to] them, sold to them by outlaw motorcycle gang members — we're not going to tolerate that."

1,300 Kiwis sent back

Lengthy detention without charge is a serious matter, and Mr Haapu's is but one case of many.

Sorry, this video has expired NZ Foreign Minister Winston Peters on the fairness of Australia's deportation system

In the past three years, the new laws have cut a swathe through many long-time Australian residents who are Kiwis, with more than 1,300 of them sent back, many of them despite having spent decades and even most of their lives, in Australia.

While many have been convicted of crimes, others like Mr Haapu have not. In the same time frame New Zealand has sent back just nine Australian citizens.

The fact our laws have fallen particularly heavily on our trans-Tasman neighbours — the only country with whom we have a relationship of free movement across borders, and that, for the better part of the past century — does not sit easily with them.

Deportee Ko Haapu was a former New Zealand soldier who was sent back to New Zealand without charge.

Specifically on the subject of Mr Haapu, the New Zealand Justice Minister was scathing:

"Detention for that length of time without charge is … I can't think of another country where … no, a liberal democratic country, like New Zealand, like Australia, like the many other western countries in the world, where that would be tolerated."

Mr Little claims Australia is exporting its problems across the Tasman.

"New Zealand has got its own gang problem," he said.

"But the police are now saying that the Comancheros are here in New Zealand. It's been established by people who have been deported from Australia, who were Comanchero members then, have been deported here, and have now simply established the gang here. It has compounded the problem that we already had.

"Australia has seen an opportunity, whether deporting people with convictions, or those who they deem to be of bad character. They are sending back problem children, so to speak, and it becomes our problem, whether they are people who've done their growing up in Australia, or they've been more recently exported from New Zealand.

"What is happening is a law that is a very blunt instrument has now simply created problems for us."

Foreign Minister and Acting Prime Minister Winston Peters expressed his deep disappointment that despite the close relationship of Australia and New Zealand over the years, it has come to this.

"The reality is we want New Zealanders to get the same treatment an Aussie would get if they were being charged with an offence. That is a trial, before you're booted off shore," he said.

Geopolitically, he makes no bones about what he sees as a strain on relations at a particularly crucial time.

"There has never been a time since 1945 that our two countries [have] needed each other more," he said.

"And, I really mean it. We've got security of all the Pacific to look at. We are senior nations with a chance to shape the Pacific and its security and its wealth. We'd better be mindful of our relationships between ourselves."

Aside from Mr Haapu, families of mixed Australian/New Zealand citizenship are being torn apart, with individual children and parents being wrested from each other.

'Breach of UN convention'

Kiwi man Shaun Wynyard lived in Australia for two decades with his Australian wife and two Australian kids.

He assaulted his wife while on the drug ice, was sent to prison, and then back to New Zealand.

Deportee Shaun Wynyard had lived in Australia for two decades with his Australian wife and Australian children when he was sent back to New Zealand.

His Australian family — including his wife, who has forgiven him — wants him home.

Discussing another case in which a teenage boy potentially faces deportation, Mr Little again pulled no punches.

"There is a case we know involving a 16-year-old young man whose parents live in Australia, but who the Australian authorities are looking to deport," he said.

"That is almost certainly in breach of the United Nations Convention on the rights of the child, but that is being considered by the Australian Government.

"I don't know. I never want to be part of a government in New Zealand that would deport a 16-year-old Australian back to Australia."

Mr Dutton, who points out the law change had bipartisan support and has received little criticism from the Opposition since, makes no apology.

He rejects Mr Little's assertion it is a breach of human rights.

"Well, we just need to see the evidence instead of the emotions," he said.

"They're New Zealand citizens, they're not Australian citizens. And it's no breach of human rights, in fact it's a breach of the civil rights of Australians who fall victims to these criminals and Australia won't tolerate it.

"It doesn't matter who we're talking about. The criteria for us is whether you've committed an offence against Australian citizens and that's the test that we apply."

In the case of Mr Haapu, we still don't know what that offence is, and he insists neither does he.

Like many of those deported, he is not an easy sell to mainstream Australia as someone we should be putting a welcome mat out to — as witness the large tattooed letters "FTP" on his neck, which stand for "F*** The Police".

It's the Australian Government's clear obligation to safeguard its people, and many Australians will undoubtedly be totally supportive of how the laws are being used.

For their part though, the deportees who've been to prison say they've paid the price for their crimes, and being separated from their families is continuing the punishment.

Many locals engaged on the topic said a lot of those suddenly arriving on Kiwi shores, a lot of the deportees that are washing up there, have been in Australia so long, "They look like Australians, sound like Australians, and whatever criminality they have has been made by Australia".

Watch Peter FitzSimons' report on Foreign Correspondent at 8:00pm on ABC TV.