'Completely unacceptable': Authorities probe mistaken release of prisoner

Victorian prison authorities are investigating the mistaken release of an inmate who was in custody for serious criminal charges.

The man was released from Ravenhall Correctional Centre on January 23 and handed himself to police the next day, Corrections Victoria confirmed today.

He had been remanded in custody on armed robbery charges, the Herald Sun reported, and returned after his mother contacted authorities to check if he should be free.

Corrections Minister Jenny Mikakos said the error is "completely unacceptable" and has demanded Corrections Victoria investigate what occurred and how to prevent it from happening again.

However Opposition Leader Matthew Guy said the incident was just one symptom of a broader crisis in the state’s prison system.

"It appears that Victoria's gone from a revolving door to an open door policy when it comes to managing our corrections system," he told reporters.

Mr Guy said there should be a broader investigation into correctional services and stressed the need for the state to appoint a new corrections commissioner.

No replacement has been announced yet for the most recent corrections commissioner Jan Shuard, who resigned in November and finished in January.