Yesterday police examined the scene near the Ballarat-Maryborough Rd overpass at Mitchell Park where the crash happened shortly before 11pm on Sunday.

The Avoca woman was thrown about 20m from the white Holden Barina in which she was a passenger after it and a green Holden Commodore collided.

Three other occupants, a 17-year-old male alleged to be driving the car, a 24-year-old male and a 10-year-old child were taken to Ballarat Health Services Base Hospital.

Four occupants of the Commodore drove away from the crash, but reported in at the police station about an hour later.

Ballarat Crime Investigation Unit Detective Senior Constable Jeff Highthorn said the occupants of the two cars knew each other.

"Two cars were travelling in a westerly direction ... it is alleged one vehicle crossed in front of the other, which rolled several times. The other car left the scene," Det Sen Const Highthorn said.

He said the drivers had spent some time driving around the district.The woman was airlifted to the Alfred Hospital shortly after the crash and was yesterday in a critical condition in intensive care.

The two males in the Barina were trapped inside the vehicle for at least half an hour while emergency service crews worked to free them.

The 17-year old yesterday remained in intensive care at the Base in a stable condition suffering lower limb fractures, while the 24-year-old received fractures to his left wrist and was awaiting surgery. The 10-year-old had been discharged.

Police have interviewed four people about the crash but have not laid any charges.

The major collision unit is investigating the incident and both vehicles are being examined.

A MAN had a lucky escape after he lost control of his Mini Moke and hit a fence last night.

The man, aged in his fifties, hit the small brick fence in Drummond St Sth about 8.10pm.

He was taken to hospital for observation with minor injuries.