Three women killed after Sydney police chase

Three women are dead, and another two people are seriously injured after a Sydney police chase ended in tragedy.

Police say officers began pursuing a white Holden Commodore in Marayong at about 1:10am on Saturday morning when it didn't stop for random breath testing.

Police say officers began pursuing a white Holden Commodore in Marayong at about 1:10am on Saturday morning when it didn't stop for random breath testing. Photo: 7 News

The car crashed at Railway Road and flipped several times shortly after the chase began, leaving two women dead at the scene.

A third woman died after being taken to Westmead Hospital, while another woman and a man are in a serious but stable condition in the hospital.

"The vehicle, we would say, sped away at very high speed and within a matter of seconds collided with a power pole," Assistant Commissioner Denis Clifford told reporters on Saturday morning.

"Unfortunately, as a result, we have three females who are deceased."

The car crashed at Railway Road and flipped several times shortly after the chase began, leaving two women dead at the scene. Photo: 7 News

Police have launched a critical incident investigation, to be overseen by the Professional Standards Command. Photo: 7 News

All those dead and injured were in the car, police told AAP.

Police do not yet know who was the driver of the vehicle.

Police have launched a critical incident investigation, to be overseen by the Professional Standards Command.

Anyone with information is asked to call Crime Stoppers on 1800 333 000.