The NSW juvenile justice system will be independently reviewed following revelations a young detainee was kept in isolation for more than 100 days in a row.
The offender was one of 66 males aged between 16-21, charged with serious offences and showing violent behaviour, dealt with under the Chisholm Behaviour Program.
"A number of detainees who had shown and demonstrated challenging behaviour did not progress through the program as it was intended because of their complex needs and misbehaviour," Corrections Minister David Elliott told reporters on Friday.
"This resulted in those detainees spending long periods in their room and on one occasion, one offender had spent 166 days out of 300 days in the most restrictive phase of the Chisholm program," he said.
Mr Elliott, who told NSW parliament in September that isolation was not taking place in youth custody in NSW, defended his previous assurances arguing "that was the information (he) had at the time".
"Because I'm not confident that that may be correct, I've asked the Inspector of Custodial Services Fiona Rafter to both investigate what is practised under Chisholm and what we should be doing in the future," he said.
The independent advisory committee will guide an overhaul of training, record keeping and governance, while a $1 million training package to help frontline officers manage high-risk detainees has also been announced.
The juvenile justice department is currently reviewing the use of time spent in rooms as part of a behaviour management review announced last week.
Mr Elliott would not confirm media reports that at least two teenagers who went through the now-closed Chisholm program were preparing to take legal action against the state government after they attempted self harm while in isolation.
"I'm confident with the quality of the work that's being done (in the youth system)," he said.
"If you're asking me, is it perfect? No. That's why I'm delighted we have Inspector Rafter looking into it and I'm very much looking forward to her response."
The government expects the review to be completed by January 2017.
Kids Helpline 1800 55 1800 (for young people aged 5 to 25).
