A riot has broken out at a Victorian detention centre amid reports a group of youths has escaped the facility and carjacked motorists.

Police were called to the "riot and escape" at Malmsbury Youth Detention Centre around 2.50pm today.

At least seven inmates are still on the run in two hijacked cars.

A police car was reportedly rammed during the escape. Seven News has reported the escapees are driving "out of control" at high speed and have smashed into a civilian car on the Calder Freeway. One of the pursuits had to be abandoned by police after an escapee started driving in the wrong direction on the freeway. A local petrol station staffer reported a "petrol drive off", just before 4pm. Police reportedly lost track of the two hijacked cars a short time ago.


Thirteen inmates initially escaped the facility but six have since been caught. Five inmates who climbed on the centre's roof have came down around 4pm and are now in police custody.

Emergency services, including police and firefighters, are currently at the correctional facility and have advised the public to steer clear of the area.

There are reports that at least one youth detention staff member was injured in the breakout.

The CFA said it was helping police with a job at the Malmsbury Youth Justice Centre on Wednesday afternoon.

The youth jail has been damaged in previous riots, which have also affected the Parkville youth detention centre.

Victoria will recruit 41 new youth justice workers after a leaked report found endemic staff shortages led to riots at the centres.

The report was ordered after riots at Parkville in March 2016, and Fairfax Media reports the government expected more riots due to low staff numbers and frequent "lockdowns" that incite unrest.

"We have boosted staff numbers and we're introducing new laws that will see tougher sentences for offenders who assault our dedicated staff," a government spokesman told AAP on Wednesday.