Victoria's youth justice system is in crisis, according to the state's opposition after a riot at the Parkville youth detention centre overnight.
A group of up to 20 inmates had broken out of the southern secure unit of the centre and were trying to force their way into another unit about 8pm on Saturday night.
Staff were evacuated and more than 35 police, including the public order response team and the dog squad, were brought in to bring a riot under control at the Melbourne Youth Justice Centre in Parkville
Youth Affairs minister Jenny Mikakos said the government had been working "around the clock" for months to improve the prison and make it fit for purpose after a similar riot in November.
"The young offenders have always sought to push the envelope and take advantage of the weaknesses in the infrastructure," Ms Mikakos told reporters in Melbourne on Sunday.
The minister says it's too early to make an assessment of the damage but it mostly relates to broken glass and very superficial wreckage.
A number of inmates also broke into the roof cavity of the building despite the minister saying that the government had been working to secure the roof space since a similar incident last year.
Opposition leader Matthew Guy said the minister was out of her depth, and called for her to be sacked.
"We're bringing in 2017 with a youth justice system in crisis, a minister in denial and a premier too arrogant to sack his minister," he said.
His colleague and opposition youth affairs spokesman Georgie Crozier called for tougher consequences for those involved.
"They know Daniel Andrews is a soft touch. So it's not just about security - it's about attitude," she said.
Victoria Police said on Sunday morning that all those involved in the disturbance were located and accounted for by about 1.20am.
Seven prisoners were removed from the facility and moved to the Grevillea Unit at Barwon Prison and the Malmsbury Youth Detention Centre.
A Department of Health and Human Services spokesman said there were no injuries during the incident and repairs would begin as soon as the police investigation is completed.
The latest disturbance follows a series of incidents at Victorian youth justice facilities, including a riot at Parkville in mid-November in which about 30 inmates trashed their cells, and another disturbance at the Malmsbury detention centre.
Some of the youths involved in those disturbances were transferred to the state's highest security adult prison, Barwon.
The youths remain in the prison's Grevillea unit in single cells despite two courts ordering they be moved to more suitable facilities.
Lawyers challenged the transfer in the Supreme Court, which found the government had acted unlawfully.
The government appealed and lost, with the Court of Appeal ordering them to move the teens, but the government instead rebranded the Grevillea unit as a youth facility.
