A 19-year-old driver who died after he crashed his car in Thornlie overnight may have been drag racing, according to police.

The man died when his car rolled down an embankment, smashed through a brick wall and ploughed into the back of a house before bursting into flames just before midnight.

Part of the back wall of the home collapsed and a crane has removed the wreck from the backyard.

Police said the driver did not have a licence.

Officers conducting speed checks noticed two cars travelling at high speed along Spencer Road just before the crash.

Detective Senior Sergeant Brian Hunter said he did not want to pre-empt the outcome of the investigation but there was "a certain amount of information to suggest the vehicles may have been racing".

"We put a lot of work into policing the roads and trying to get the message out there, particularly to young people, to drive safely," he said.

"It’s tough for the officers investigating these matters.

"They see some pretty gruesome sights, and we have to break the news to the families."

Police said the male driver of the second car knew the victim and has been interviewed.

Forensic experts have examined the scene and are calling for anyone who may be able to offer information to contact them.