Another assault on staff at the troubled Malmsbury Youth Justice Centre has left staff shell-shocked and cast doubt over how the facility is being operated.
There is regular violence at the centre in central Victoria, which houses 51 young men aged between 15 and 21 years.
Two of the most-senior managers at the facility were seriously assaulted and hospitalised last week, in what staff have described as the centre's most brutal assault in years.
The ABC understands that the men — experienced operations managers who have both recently acted in the role of deputy general manager at Malmsbury — were targeted in a planned assault on Thursday afternoon in the high-security Monash unit.
Colleagues say the two managers are highly respected, and the serious assault has shaken staff and led to calls for the centre to be closed.
"Management has to stand up and support the staff, because nothing is going to happen until, eventually, a staff member is killed," former staff member Ken Rose said.
"The government needs to step in.
"There needs to be more staff and harsher penalties [on clients] for assaults."
The youth justice centre was in lockdown for most of Friday, as staff feared for their safety.
"It's shattering," a current staff member said.
In an internal email obtained by the ABC, Malmsbury management told staff it had been a "very difficult and emotional week" with "incidences of unacceptable violence".
The email acknowledged that, at a staff meeting on Friday, a day after the latest attack, "the CPSU and WorkSafe implored us to do more".
In the email, management did not say what more could or would be done to protect staff.
Injured staff member 'may not work again'
The ABC understands the two senior managers had ordered that a young person from the Monash secure unit be moved to what is called the Intensive Supervision Annexe because of the risk the young person posed to staff and other young people.
Other young people objected to their friend being removed and both operations managers attended the Monash unit to address the young people about the decision, to "set boundaries, and ensure floor staff were supported", the ABC has been told.
It was during this address to the young people that the managers were attacked.
The ABC has been told the group of young men waited until they had an opportunity, separated the managers and commenced the assault.
It's understood the group dragged a 60-year-old manager into a corridor and assaulted him.
The man remains in hospital with multiple facial fractures, a broken jaw, two broken eye sockets, an injured shoulder and lacerations.
It is understood his injuries are so severe he may not be able to work again.
The ABC has reported at least four youth justice workers have received large compensation payouts after being traumatised by working at Malmsbury Youth Justice Centre.
Meanwhile, the state's Department of Justice declined to comment on the specifics of the assault, nor how it would impact on the centre's operations.
"The safety of staff in youth justice is of utmost importance — violent behaviour isn't tolerated, which is why there are strict laws in place that ensure tough consequences for young people who assault custodial workers," a department spokesperson said in a statement.
WorkSafe Victoria and the Community and Public Sector Union (CPSU) attended the Malmsbury centre on Friday and met with staff.
Neither body responded to interview requests from the ABC.
Opposition Youth Justice spokesman Matthew Bach and Workplace Relations spokesman Nick Wakeling have written to WorkSafe and the Victorian Children's Commissioner, asking them to launch a substantive inquiry into youth justice.
"It is quite apparent that the current environment in Victoria's youth justice facilities is unsafe for workers and not conducive to rehabilitation for young people," the letter reads.
Youth Justice Minister Natalie Hutchins said the attacks concerned her.
"I've been in regular discussions with the commissioner regarding the events that occurred at Malmsbury last week, and have been assured that staff are being supported during this difficult time," she said.
"I am deeply concerned whenever there are any incidents of violence involving our dedicated youth justice workers, and these matters are treated incredibly seriously."
The four young people responsible for the attack have been moved to Parkville Youth Justice Centre, which has its own understaffing and safety issues.
The ABC understands young people at Malmsbury have made threats against different staff since their two managers were hospitalised.
