"A day at Malmsbury is just horrific," an ex-staffer, who wished to remain anonymous, said.

They said workers were regularly faced with threats of assault and verbal abuse.

"Day after day this does take a toll," they said.

They were aware of at least five assaults on staff in the past two weeks.

Community and Public Sector Union spokesperson Julian Kennelly said he was aware of 311 assaults on staff at Malmsbury Youth Justice Centre in the first 120 days of 2019.

He attributed unrest at the centre to a small cohort of young people - roughly 10 per cent of the facility's population.

Macedon Ranges Crime Investigation Unit detectives are expected to charge a 17-year-old boy on summons with recklessly causing injury following an incident on Wednesday, in which a member of the Correctional Emergency Response Team sustained injuries to his upper body.

A Community and Public Sector Union spokesperson said the worker was believed to have been attacked by a young offender armed with an improvised weapon.

The spokesperson believed youth justice workers had attempted to search the young offender's room on suspicion of cannabis use. CERT was called after the young person resisted the search.

Another two staff members were taken to hospital on Thursday with cuts and bruising after a second assault.

The ex-worker said the two incidents that had come to the public's attention were the most serious of the alleged assaults they were aware of from the past two weeks.

They were concerned violence against staff at the precinct was escalating, and said workers had little capacity to protect themselves.

The ex-staffer said the centre's 'clients' had more protection than employees, under the Children and Young Persons Act.

"It's the staff that need the protection," they said.

"I just don't understand why they don't have the same rights as emergency services."

They were aware of staff members who had sustained life-changing physical and emotional injuries in the course of their work.

"At least 20 people I worked with that stuck in there have filed claims with WorkCover," the former worker said.

They questioned how many would feel safe and supported enough to return to work.

The ex-worker was still living with the effects of trauma they had been exposed to at Malmsbury, not all of which was directed at staff.

"You never really do get over it," they said.

They said both government and the justice system needed to look at the structure of youth justice.

"If nothing is done... God knows what we're going to end up with," they said.

A concerned staffer, who wished to remain anonymous, said the clients were running the precinct.

They said risk assessments weren't being performed and workers who had only a few months of experience were being left in charge of units, with little to no support. The worker said staff were scared and wanted to feel safe.

"The place needs an overhaul," they said.

Youth justice centre staff yesterday enacted a health and safety cease work. They met management and with Worksafe about what was needed to make the site safe to return to work.

Discussions were still ongoing on Friday afternoon.

A Worksafe spokesperson said Worksafe had visited the Malmsbury Youth Justice Precinct and was investigating a number of incidents.

Minister for Youth Justice Ben Carroll reiterated that assaults on staff at youth justice centres wouldn't be tolerated.

He said the behaviour seen on Thursday was "appalling and our staff shouldn't have to put up with it."

"The safety of our hard-working and dedicated staff is paramount and violent behaviour or assaults at youth justice centres won't be tolerated," Mr Carroll said. He said he had been briefed on the situation.

"My focus is on supporting all of our youth justice workers," he said.

"Tough new laws are now in effect - which we introduced - that strengthen consequences for young people who assault youth justice custodial workers or damage property.

"This includes a presumption they will serve their sentences on top of an existing period of detention."

He said the government had made unprecedented investment of over $1.2-billion on the youth justice system for new and upgraded facilities, additional staff, and expanded programs and interventions for offenders.

Victorian opposition leader Michael O'Brien said violence against staff members at the youth justice precinct was a real concern.

"Not only are staff not safe, but these young offenders are turning out more violent when they leave than when they arrive," he said.

He said the government had lost control of the youth justice system and needed to urgently step in to ensure staff were safe.

"Make sure these young offenders are not allowed to continue with this sort of behaviour and make sure they are rehabilitated so that the public is safe when they are released," Mr O'Brien said.

"We've seen staff not having the right resources or the support they need to get these young offenders back under control."

He said the youth justice system needed more staff, more resources, and the right facilities to keep violent offenders away from the general population in youth justice precincts.

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