Violence and disturbances became "commonplace" as teens exploited infrastructure weaknesses in Victoria's youth justice system, a report has found.
Youth justice staff are also ill-equipped to deal with the offenders, who are increasingly showing no respect for authority.
Former chief commissioner Neil Comrie was called in to review the system after a series of riots in Melbourne's Parkville youth justice centre in November.
Youths smashed through ceilings, climbed onto roofs and threatened staff with makeshift weapons during the November riots - the latest in a string of incidents.
"It is clear that a defining point has been reached in the long history of youth justice in Victoria," Mr Comrie wrote.
"Infrastructure, policy and systems that were designed and built for a different era have proven to be incapable of delivering the imperative of a safe and secure youth justice system in 2016/17."
He said the incidents led to an environment where violence and disturbances were commonplace at youth justice centres.
Part two of Mr Comrie's review was released on Tuesday, making 11 recommendations including better training for staff.
All of the recommendations have been accepted by the government.
Youth Justice was transferred from the Department of Health and Human Services to the Department of Justice and Regulation on Monday.
The sector is under massive scrutiny following the riots and a mass escape from the Malmsbury youth justice centre in January.
The riots rendered parts of Parkville uninhabitable so the government moved some detainees to a unit in the adult Barwon prison.
That decision sparked several court challenges, the latest starting on Monday.
A parliamentary committee and the Commission for Children and Young People are currently investigating the system.
And the government will also soon receive the Youth Justice Review being undertaken by experts Penny Armytage and Professor James Ogloff.
It was announced in February that a new youth prison would be built west of Melbourne.
