Police have released CCTV footage in a bid to find three young men who allegedly fled the scene of a car crash in western Sydney, leaving a female passenger to die on the side of the road.

The woman, believed to be aged between 25 and 35, was in the station wagon with the men when they crashed into a concrete traffic island and then a power pole in Chester Hill about 6.30am yesterday.

media_camera Debris scattered on the road after the fatal crash at Chester Hill. Picture: Top Notch Video

The men allegedly fled after pulling her from the wreckage and leaving her on a footpath to die.

Police early this morning released CCTV footage of a man they believe can assist in the investigation and also appealed for public assistance in identifying the Asian woman who died and the three men involved.

Police believe the men could be illegal immigrants.

media_camera CCTV of man wanted over a crash at Chester Hill which killed a female passenger. Picture: NSW Police

Heidi Karlson ran to the scene after hearing an “almighty bang” from outside her apartment.

“She was unconscious and in a ­terrible state,” Ms Karlson, 41, said.

“I felt her pulse and checked her airways. I started CPR. I then felt for her pulse again but she was gone.”

Ms Karlson then covered the victim, who she described as a “pretty girl”, and waited for the ambulance.

“I’m going to pray for this girl. I can’t believe that they could drag her out of the car and then just leave her there. I can’t stop thinking if they just left her in the car, maybe she would’ve survived. I held her hand as she died. I just want her family and the people who love her to know that she did not die alone,” she said.

media_camera Police on the scene after the death of a woman. The hunt is on for three passengers who fled the scene. Picture: (Jason McCawley/News Corp)

The car was full of white paint, which exploded over the road.

Detective Chief Inspector Phillip Brooks, from the Traffic and Highway Patrol Command, said the incident was shocking.

“Not only is this a tragic event, it is also cowardly that they would leave a young lady without providing first aid before fleeing the scene,” Insp Brooks said.

“This death takes this years road toll up to 186 people.”

Soon after the incident police knocked on the door of the car’s registered owner, who lives in Lidcombe.

media_camera The car crashed into a power pole, killing the woman. Picture: (Jason McCawley/News Corp)

He was not home, so police are continuing to search for the trio. Police believe the car was not stolen.

“From the amount of household paint in the car it’s a possibility that they are a painting crew,” Inspector Darryl Hawes said.

Fatal car accident in Chester Hill 4:15 Police are investigating an accident which has left a person deceased in Sydney's west overnight. Fatal car accident in Chester Hill

“They obviously give little regard for human life.

“There is a possibility that they are illegal immigrants doing cheap work.

“However, we have not confirmed the identification of anyone.”

The female victim was wearing a jacket, long pants and work boots.

Police are reviewing CCTV footage from the scene.

media_camera Witnesses say the men in the car tried to stop them calling police. Picture: (Jason McCawley/News Corp)

Uber driver Danish Umer, who pulled over to help the woman, said one of the men tried to stop him.

“One of the guys tried to hold my hand and tried to stop me to call the police or paramedics,” he told the Seven Network.

“I tried my best to save the lady but she was dead.”