Sydney man 'arms himself with chainsaw' after motorcycle crash

A motorcycle rider who fled when he hit a four-wheel drive armed himself with a stolen chainsaw and two screwdrivers before being subdued by members of the public in Sydney’s west.

The man, believed to be in his 40s, sustained head injuries when he ploughed into a car in Kemps Creek today.

Despite his injuries, police said he fled the scene, stole keys from a hairdresser and attempted to steal a parked car.

"Well I saw him run into the hairdresser's store with blood all over his face," Jessie Gauci told 9News.

Another witness, Harrison Gauchi, said he ran around trying to assault members of the public who were trying to catch him.

During the ordeal, he allegedly also stole a chainsaw and other tools from a nearby home.

"He had two screwdrivers and then the police came," Harrison said.

Passers-by had detained the man before police took him into custody. He was taken to Liverpool Hospital where he remains under police guard.

No charges have been laid.