A night out in Brisbane celebrating his 21st birthday has turned into exile in New Zealand for a young Australian man.

Photo: 123RF

His mother has spent the last week settling her son into his new life in Christchurch and neither of them can believe he's been deported following what was a Saturday night out with friends.

"It's pretty upsetting I guess, yeah, I mean it's been a good week but, yeah, I'm not gonna see him for a while," said Maria.

RNZ has agreed not to use the family surname or name her son, as he is worried it might damage his job prospects.

The Australian government has ruled he is a possible risk to the health or safety of the community he's lived in since he was six years old.

"I don't reckon the consequences are what it should have been ... it's unfair, it's unjust," he told RNZ.

His family are now at the pointy end of Australian immigration law which they are experiencing as a minefield for young males without citizenship.

"Don't let them out at night," Maria advised, laughing bitterly. She is a professional, her husband is a train driver.

"But you can't do that. You can't tell that to teenage boys, so ... we'd always raised [our son] to drink responsibly, to do the right thing, but ...'

He had had three years of run-ins with the police before he went out for his 21st in July and, with friends, ended up in a fight.

It's unclear exactly what happened as the case has never gone to court. Under the law's section 116, a conviction is not necessary for deportation.

The young apprentice printer admits he drank too much, but says that by sticking around, trying to resolve things, he ended up jailed, on a charge of entering a dwelling with intent at night and threatening or using violence.

"It wasn't as serious as it was made out to be, it was just blown out of proportion."

His parents got a call that he was in jail.

"We didn't even realise how serious it was until we went to the lawyer to try to get bail for him and they said that the charge was quite serious.

"When eventually we did get to speak to [our son] on the phone ... he said, 'It's not what it seems, mum'. And so then we thought, OK, it's gonna sort itself out."

They were wrong.

Their lawyer filed papers to reduce the charges.

But the Immigration Department got in first.

"They didn't contact our lawyers to get any information, they didn't contact anybody.

"It feels like a lottery. There was a suggestion, at one point, that he puts himself into remand so Immigration can't take him until it goes to court. But he didn't want to go back to prison, he's not a criminal."

She had carried on believing everything would be OK. "I thought someone would see sense," said Maria.

However, in September they got a letter citing her son's two other public nuisance convictions and three run-ins with the police since he was 18, resulting in charges but no convictions, and with fines totalling about $2000.

That record "indicates you hold a general disregard for Australian laws and values", Immigration said.

The latest charge showed he was "a risk to the safety of the alleged victim".

His employer, who runs a family printing business, helped him appeal.

"He is our youngest team member and shows great leadership within his finishing team," his boss wrote. "He is committed to his job and is hardworking and reliable.

"I have seen a great improvement in his level of maturity and responsibility over his time with us, I have high hopes he will stay with us for many years to come."

A senior teacher at his former high school also wrote in support, as did the young man himself: "My prior history resulted from doing some minor and silly things all from being drunk and disorderly.

"I realised some time ago that drugs and excess alcohol are wrong so I decided to ... stop this behaviour ... and have kept out of trouble until this recent incident."

It wasn't enough.

The Immigration Department's Cancellations Officers only have to show someone "is or may be or would be a risk", according to section 116, a law Australia appears to be using more often to deport New Zealanders.

"Anybody is a 'may be'," said his mother. "Any person, [though] probably more likely the younger males, the 21-year-olds, the 18-year-olds."

Her son went to the police station for a regular reporting-in in November, and was detained.

Maria said he was told he might be sent to Christmas Island detention centre but instead was deported.

Unlike with the many detainees held under the law's section 501, who aren't deported unless they sign up to be, section 116ers can be.

Her son was still living at home when this happened, their 23-year-old daughter has just moved out.

They have decided to make staggered visits to Christchurch: Maria one time, her husband the next, so their son gets to see more of them.

It would be a different Christmas for them, she said.

"I'll be all right," said their son. "Starting a new life. Just gotta get on with it I suppose."