The Community and Public Sector Union said the agreement included new rules about young offender behaviours and expectations around behaviours, with 'zero tolerance' for violence against staff.

The union said the agreement would "give power back to staff to make decisions in units as issues become apparent."

It said WorkSafe had issued notices against the Department of Justice and Community Safety under Victoria's health and safety laws.

A partial centre lockdown, which started on Friday, will be gradually lifted as the new rules are communicated to young offenders, unit by unit.

"The parties agreed to continue to discuss strategies around maximising staff in units, with the department acknowledging that staff had the power now to re-secure offenders if staffing was not adequate," the union said in a statement.

It said a recruit course being implemented through induction would deliver additional staff resources for the centre.

"Sunday's and yesterday's roster were almost full as absent staff returned," the union said.

A WorkSafe spokesperson said investigations at the youth justice centre were continuing.

The department reiterated its investment in youth justice, which exceeds $1.2-billion.

"A modified design of the new Cherry Creek youth justice centre was announced in September this year, along with the continued operation of the Parkville and Malmsbury Youth Justice Centres," a spokesperson said.

"Cherry Creek has been revised to deliver a more specialised facility that focuses on staff safety and reducing re-offending among Victoria's most complex and challenging young males aged 15-18 years."

Features will include more secure accommodation units, an intensive intervention unit for high-risk young people, eight dedicated mental health beds, and advanced technology to monitor movement.

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