A scathing review of three Victorian youth prisons has found children and young people are being "damaged rather than rehabilitated" through "excessive isolation" which is "unlawful, wrong" and "incompatible with human rights law".

Key points: Ombudsman Deborah Glass said solitary confinement could lead to long-term harm

Ombudsman Deborah Glass said solitary confinement could lead to long-term harm She found an "alarming" number of young people were in prolonged isolation at Port Phillip Prison

She found an "alarming" number of young people were in prolonged isolation at Port Phillip Prison One young prisoner was held for 18 days despite being cleared of a crime

Victorian Ombudsman Deborah Glass inspected Port Phillip Prison, Malmsbury Youth Justice Precinct and Secure Welfare Services earlier this year and found children and young people were often separated for weeks at a time even where there was little or no ongoing risk to others.

Youth prisoner Jake experienced a traumatic childhood; he was abused, exposed to family violence and was eventually incarcerated.

An allegation of assault on another prisoner at a Victorian jail led to Jake being isolated for 432 hours, or 18 days, despite being cleared of the assault during his seclusion.

"Legislation and official procedures acknowledge that children and young people should be isolated only as a last resort and for the minimum time necessary," Ms Glass said.

"But we found the procedures do not translate into practice."

Weeks of isolation 'a serious risk' for young people

There were 1,214 isolations for behavioural reasons in a year at the Malmsbury centre, according to the latest Ombudsman report. ( Victorian Auditor General's Report )

Ms Glass said there was an example where a boy called Trent was isolated for 20 days because he was found with an anti-depressant pill.

"I don't doubt that was an offence under prison regulations but does that justify weeks of isolation?" she said.

The report found Port Phillip Prison was separating young people at a higher rate than adults and was particularly "ill-equipped" to deal with the challenging behaviour of young people, with isolation being the preferred behavioural tool rather than the exception.

"Children and young people can be irrational, volatile and unable to self-regulate, presenting behaviour that is more challenging and extreme than many adults," Ms Glass said.

"But it is time to look beyond the tough-on-crime rhetoric to consider what will genuinely lead to safer communities and safer correctional facilities."

Ms Glass said research showed that until about 25 years old, young people were still developing physically, mentally, neurologically and socially.

"[Which] is why solitary confinement on children and young people poses such a serious risk of long-term harm," she said.

Report makes 27 recommendations to State Government

The report, tabled in Parliament today, makes 27 recommendations to the State Government, including that it prohibit solitary confinement in law and review how young people are managed in the corrections system to move them out of mainstream Victorian prisons into a dedicated facility.

Law Institute of Victoria president Stuart Webb said the report showed disturbing practices in youth justice and prisons.

Mr Webb said it was time to come up with remedies to keep young offenders secure while maximising rehabilitation prospects.

"The Law Institute of Victoria strongly supports the recommendations made by the ombudsman including recognising the negative impacts solitary confinement has on children and young people," he said.

Minister for Corrections Ben Carroll said the Government welcomed the Ombudsman's report and was currently considering the recommendations, with work already underway to implementing a number of them.

"We make no apologies for making sure these facilities are as safe and secure as possible for our hard-working staff and young people."

"You can't rehabilitate young people in an unsafe environment — that's why we've invested $1.2 billion over the past four years to overhaul the youth justice system."

"We've delivered more staff, stronger and safer infrastructure, expanded rehabilitation programs, and more mental health services for young people."