CCTV shows driver of hit-run crash calmly walking away from wreckage in Geelong

Police are searching for a hit-run driver who appeared to calmly walk away from a crash that trapped two of his passengers and left another seriously injured in Geelong, Victoria.

Emergency services were called to the scene after a red Holden Commodore sedan collided with a silver Mazda hatch on Barwarre Road in Marshall, in the city's south, about 6.15pm yesterday.

Police said the Mazda driver was airlifted to hospital with life-threatening injuries but they were told the male Commodore driver "dumped the vehicle and fled on foot".

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The woman remains in hospital in a serious condition.

His two passengers, a man and a woman, remained behind and were both taken to hospital with minor injuries.

Witnesses have told media the sedan was allegedly travelling "very fast" in the moments before the crash.

"I heard a really loud bang. I went over there and there was a lady crying out in pain and I kept her calm. I did hear that the driver ran off and the lady I spoke with asked where he was," she said.

"There was a lot of debris so they hit very hard."

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Police are still investigating exactly what happened in what they termed a "hit-run collision".

They called on anyone who saw the crash or had footage of it to contact Crime Stoppers on 1800 333 000 the website.