Exclusive: 'A new low' as Kiwi teen held in Aussie detention centre against UN protocol

A Kiwi minor being held in a Melbourne detention centre is a "new low" for Australia's system, according to the teenager's lawyer.

The 17-year-old's detention in an adult facility goes against the UN's Rights of the Child, and his supporters believe his health is at risk.

Behind the wire at Melbourne's Magar Barracks, Australia's unwanted are locked away.

The detention centre known as MITA (Melbourne Immigration Transit Accommodation) lies at the end of the road - in more ways than one.

Immigration lawyer Greg Barns says the Kiwi teenager's imprisonment is emblematic of wider issues with how the country treats its immigrants.

"Australia has a particularly cruel immigration system, and has had for 10 years or more - but this is a new low."

He's one of two children in the adult facility, and can't be named because he's a minor. But that's also why his lawyer says he shouldn't be there: detaining a minor in an adult facility is against the UN Convention on the Rights of the Child.

"You should never put young people, 16, 17 years old, in adult detention facilities," says Mr Barns. "It causes enormous amounts of harm."

 Access to the centre is closely guarded, and Newshub was refused permission to film.

Freelance journalist Rebekah Holt has spoken several times to the young New Zealander. She says the conditions are affecting his health.

"He's very vulnerable right now," says Ms Holt. "I'm tremendously worried about him. He's not sleeping properly, he's not eating properly."

His conditions are about to get worse. Since Newshub inquired with the Australian Border Force (ABF), he's been told he'll lose his computer access.  With no cellphone - and nine hours' drive from his family - he'll be almost shut off from the outside world.

Australia's deported hundreds of Kiwis who have served prison sentences of 12 months or more.

But the 17-year-old spent only months in a New South Wales juvenile facility. Newshub understands it was a non-violent crime.

"There's nothing about this young person's antecedence which would make him a threat to good order in Australia," says Mr Barns.

The Australian Border Force didn't answer specific questions about the legal basis for detaining a child, but a spokeperson said the ABF is committed to keeping minors out of detention.

"However from time to time there may be occasions where minors will be temporarily held in immigration detention," they said.

"This could be as a result of airport turnarounds, people who are in the final stages of removal from Australia, or due to criminal or security issues."

Australian Children's Commissioner Megan Mitchell has expressed concern about cancelling the visas of minors in the past.

In a statement, she said children should "only be detained as a measure of last resort and for the shortest possible period of time".

"We know that prolonged detention can have a profoundly negative impact on the mental and emotional health and development of children."

The Kiwi teen has been in detention since March and will remain there until at least July, when his deportation hearing is held.