The incident occurred about 7.45pm on Monday, and left one car, a dark Citroen hatchback, on its roof. The other car, a blue Ford sedan towing a trailer, was badly damaged.

No one was injured in the crash, and Ambulance Victoria confirmed no patients were treated.

The intersection at the corner of Stawell Street and Charlesworth Street was blocked by police tape as investigators established a crime scene.

Witnesses at the scene said they saw three or four people run from the crash - one of them appearing to be a young woman, and at least two males.

There were early reports of an axe being seen.

Ballarat Highway Patrol's Acting Senior Sergeant Stuart Gale confirmed police were investigating an assault "that occurred after the collision, and the circumstances surrounding that".

"There's a number of items from the vehicle being collected, they will form part of this investigation," he added.

Police were seen examining an Adidas backpack and other personal items extracted from the Citroen, with some items seen being placed in a sharps container.

A large number of onlookers were at the scene, which was in front of a caravan park.

As of deadline, it is unknown if any arrests have been made.

Anyone with information or dashcam footage is urged to phone Crime Stoppers on 1800 333 000, or the Ballarat police station on 5336 6000.

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