Two teenage girls were airlifted to hospital on Wednesday following a serious collision along the Great Ocean Road.

The two girls were in a small Holden sedan which collided with a bus at Separation Creek.

It's believed the driver of the bus suffered a medical episode which caused the driver to lose control of the vehicle.

A female teenager was flown to The Royal Melbourne Hospital and a second female teenager was flown to The Royal Children’s Hospital.

The bus carrying 11 passengers collided with a silver Holden Commodore Sedan car with the two female occupants.

The accident left the section of the road between Wye River and Lorne closed for much of the day.

Three others were taken by road ambulance to hospital treated for minor injuries.