The Northern Territory's acting commissioner for children has launched an inquiry into transfers from the Alice Springs youth detention centre to the notorious Don Dale facility.
The government's Territory Families agency flagged the move in December, saying it was needed so the Alice Springs centre could be upgraded.
But advocates and Aboriginal legal experts say moving already vulnerable children 1500 kilometres away from their families is likely to cause more harm.
The government would be better off investing in programs to keep kids out of detention in the first place, they said.
The reduction of capacity at the Alice Springs centre and subsequent transfer of young people to Don Dale in Darwin began on Friday.
Acting Children's Commissioner Nicole Hucks said in a statement she had launched the inquiry because requests for further information and critical details on the transition had not been met.
Justice Reform Initiative executive director Mindy Sotiri told AAP that there had been a dramatic increase in the number of children in detention in the NT since 2021 changes to youth legislation, which removed the presumption of bail for first-time offenders and automatically revoke bail if conditions are breached.
"The Northern Territory is just incredibly out of step in terms of the increases of the numbers of children in detention over the last few years compared to almost everywhere else in Australia," she said.
"We're spending all this money on locking children up, which we know doesn't work to keep the community safe.
"We know, in fact, that prison is criminogenic, it makes it more likely that children will go on to commit more crime and have more contact with the criminal justice system."
Dr Sotiri said instead of throwing more money at youth detention, the government should be looking at ways to effectively address the drivers of crime, including poverty.
"Most children are going in to detention because they're on remand for quite short periods of time but that is an incredibly disruptive and harmful experience for both that child who is in custody and also for the family and community on the outside," she said.
Most children in need are unable to access alcohol and drug treatment, or support with mental health and disability, she said.
Minister for Territory Families Kate Worden said in a statement upgrades of the Alice Springs centre were among recommendations of the 2016 royal commission and will make the facility more fit to support young people.
"Any transfer being undertaken will be informed by operational demands and take into consideration the needs of young people, and managed in close consultation with their family, legal representatives and service providers," she said.
In 2016, the NT held a royal commission in the wake of evidence showing abuse and torture of Aboriginal children at Don Dale.
The commission made a series of recommendations regarding reform of the system, but critics say the government has been too slow to implement them.
