A doctor stabbed by an inmate at a Melbourne psychiatric hospital has been discharged from hospital and is recovering at home.
The female doctor was attacked on Tuesday by a male patient at the Thomas Embling Hospital in Fairfield, operated by Victorian government authority Forensicare.
Her attacker was found not guilty of shooting dead two students at Monash University in 2002 due to mental impairment, the ABC reported on Wednesday.
Police are investigating but would not confirm the man's identity.
In a statement issued late on Wednesday, board chairman Bill Healy said Forensicare would co-operate with an investigation ordered by Health Minister Martin Foley.
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"We welcome the minister's announcement that the government will conduct a full and proper investigation into the circumstances surrounding this incident and Forensicare will co-operate fully with the investigation," he said.
The incident occurred in the hospital's Jardine Unit, where patients receive intensive rehabilitation and learn independent living skills.
It's understood the man was recently moved to the less secure unit.
The Health and Community Services Union is demanding an urgent review into staffing levels and protocols at Thomas Embling.
It wants the state government to consider immediately removing patients who assault or threaten staff.
A union spokesman said staff had been trying to highlight the risks they faced for the past two years.
"Whilst this was a particularly nasty incident, they have been facing ongoing violence all the time," he told AAP.
Union research shows a third of the mental health workforce have experienced a physical assault.
That figure is higher in forensic services, which provides mental health care for people in the criminal justice system, the union says.
But those patients are often not taken into custody, investigated or charged by police after they assault or threaten staff, even if the incidents are reported to management.
"There are concerns about a culture that's developing where patients feel they can assault staff with impunity," the union spokesman said.
