Forensicare's recent annual report shows there were 120 patients admitted to the state's secure forensic mental health hospital in the last financial year.

But forensic patients in prison waited an average of 319 days to be admitted to the Thomas Embling Hospital following a recommendation to the court for a custodial supervision order.

Forensicare provides adult mental health services in Victoria for people involved in the criminal justice system.

The recent annual report said changes to sentencing and bail laws had seen a large increase in remandees, placing significant pressure on prison mental health services, as well as the bed capacity at the hospital.

"This unprecedented demand for our services is placing greater strain on the mental health system, particularly in managing complex forensic consumers in the community," the report said.

"Increasing our resources, as well as the recruitment of suitably qualified staff (and ensuring the health and safety of our current workforce) is therefore a priority."

The report showed five men had their criminal trials adjourned because there were no Forensicare services available due to a lack of available beds at the hospital.

Long waits for cases to reach trial can prove stressful for defendants, victims and witnesses, preventing them from moving on from the crime and hindering their recovery.

The report also revealed there were 367 pre-sentence psychiatric and psychological reports conducted in the last financial year for people either in custody or on bail.

But matters are often adjourned for months at a time as the courts wait for those reports.

Earlier this month, a magistrate told a suicidal Warrnambool man it would take up to three months for a pre-sentence report to take place.

And in August, a 38-year-old Timboon man pleaded guilty to family violence-related offending but was refused bail and ordered to undergo a Forensicare report. He remains in custody.

The time it takes to prepare a court report is dependent on the history and complexity of the court case and person involved.

Minister for Mental Health Martin Foley said there continued to be a high demand for compulsory treatment services for prisoners.

"We're working to reduce wait times and have recently opened a new intensive psychiatrist care unit at Thomas Embling Hospital to help address this," he said.

"We know our current mental health system is not working, which is why we've established the Royal Commission into Victoria's Mental Health System.

"The Royal Commission's interim report is due in November and we have promised to implement every single recommendation."

South West Coast MP Roma Britnell said Victoria's mental health system was at breaking point.

"And the Andrews Labor Government's answer is to wait for the results of the royal commission into Mental Health," she said.

"But while we wait for that much needed investigation to be completed the system is letting people down. We can't just sit and wait, even the Victorian Auditor General said we cannot wait for the royal commission to start fixing the issues we are seeing.

"While the Royal Commission into Mental Health is vitally important to look at changing the mental health system as a whole - there are things that can be changed now to help ease the burden which is leaving people in a desperate situation feel let down by the system."

Mental health treatment in prisons is voluntary and prisoners are seen by clinicians while they're waiting for a hospital transfer.

If a person in prison is unable or unwilling to accept mental health treatment, they can be recommended for compulsory treatment at Thomas Embling Hospital.

That means people accepting voluntary treatment may wait for a longer period of time for a bed.

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