A woman has been found dead on a footpath in Sydney's west after the car she was in crashed early on Saturday morning.

Police said the woman, believed to be in her mid 30s, was found after the car she was in lost control, hitting a concrete traffic island and a power pole on Waldron Road in Chester Hill.

Officers said they believed she was sitting in the back left-hand seat that took most of the impact.

Three other people who were in the car took her body to the side of the road after the crash before running away.

The woman has not been identified.

Detective Chief Inspector Phillip Brooks said police believe speed was a factor in the crash.

"For these three young males to be involved in this crash, to pull this young woman out of the car and then leave her to die by the side of the road is certainly a very significant factor in this very sad and tragic event," he said.

"It's a clear lack of personal responsibility which is costing lives on NSW roads."

Paint and tools spread across road

Chief Inspector Brooks said the car was loaded with a large amount of house paint and other tools that ended up strewn across Waldron Road.

Police are searching for three men who fled the scene after the crash in Chester Hill. ( ABC News )

"It's quite obvious that a significant amount of paint was left on the roadway after this crash and potentially these people are involved in the painting trade," he said.

"Tradesmen themselves potentially may know who these people are based on the description of this vehicle in the media today."

He said no-one was found at the address of the registered owner of the car, a Holden Commodore station wagon, and he has appealed for them to come forward.

"The driver knows who they are and they are compelled to attend the nearest police station and present themselves to police," he said.

Bankstown Local Area Command and police from the Crash Investigation Unit are looking into the incident.