By Ashleigh McMillan, Goya Dmytryshchak and Tate Papworth
Parkville's troubled youth justice centre is expected to remain in lockdown overnight and into Monday.
Prison workers have been told to stop work a day after a food fight in the centre resulted in three staff members being punched and taken to hospital.
The facility was in lockdown on Sunday afternoon, with staff remaining on-site to monitor units.
The outside of the Melbourne Youth Justice Centre in Parkville.Credit: Luis Ascui
An investigating officer from the Community and Public Sector Union remained in safety discussions with centre management on Sunday afternoon.
The discussions focused on the management of violent detainees and an agreement to implement policies similar to those in place at Malmsbury Youth Justice Centre, including stricter movement control and giving unit staff the authority to lock down when they sense trouble.
WorkSafe officers also attended the facility on Sunday and are expected to return on Monday.
Paramedics were called to the centre about 2.30pm on Saturday after reports three men had all been punched in the head.
Victoria Police spokeswoman Creina O'Grady said police would investigate the assaults.
"Investigators believe three youths, who reside at the address, were involved in the assault and they are expected to be interviewed at a later date," she said.
The union had requested management lock down the facility for inmates aged over 15.
It follows a 'six versus one' assault on another Parkville worker on November 10, who was taken to hospital with facial fractures after he was assaulted when he tried to break up a fight.
The CPSU's Victorian branch assistant secretary Wayne Townsend told The Age last week an "interim" facility needed to be brought into use to reduce pressure on justice centre staff before the new Cherry Creek youth justice facility is built in 2021, west of Werribee.
"We intervene to stop them killing someone else and our officer ends up in hospital," he said.
More than half the Parkville facility needed to be shutdown by Corrections Victoria after rioting inmates infamously destroyed large sections of the centre in late 2016 and early 2017.
In September the state government shelved plans to shut down the troubled centre, despite an earlier Ombudsman’s report warning it needed to be closed.
At the start of October, the Malmsbury Youth Justice Centre was plunged into lockdown, after an offender allegedly picked up a plastic cricket bat and lunged at a guard before repeatedly striking him to the head, then kicking him when he fell to the ground.