Two people have died after their car became caught between two trucks and burst into flames on the Princes Motorway in Wollongong, south of Sydney.

Key points: Two trucks and eight cars were involved in the collision in West Wollongong

Two trucks and eight cars were involved in the collision in West Wollongong Two people in one of the vehicles were incinerated while nine other escaped with minor injuries

Two people in one of the vehicles were incinerated while nine other escaped with minor injuries Police are appealing for witnesses to come forward with dashcam footage

Emergency crews were called just after 3:00pm following reports of plumes of smoke on the M1 Princes Motorway near the Mount Keira Road overpass at West Wollongong.

Two trucks and eight cars were involved in the collision and police have confirmed two people in one of the cars have died.

Police Superintendent Chris Craner said the exact cause of the crash is unknown.

"We have had an absolute tragic loss of life here on the roads at Wollongong," he said.

"Two people were incinerated in a motor vehicle that has been caught between two trucks.

"The exact circumstances … we are trying to piece it together. We are trying to interview people we have taken people back to the police station."

Superintendent Craner said the truck driver behind the car managed to jump from the cabin and was not injured.

The truck behind the engulfed vehicle also caught alight and the driver was able to jump to safety. ( ABC Illawarra: Nick McLaren )

Nine people were treated at the scene by paramedics, but none needed to be taken to hospital.

A number of people in the other cars have been taken back to Wollongong Police Station to give witness statement and give blood and urine samples.

Chief Inspector of the NSW Ambulance Service, Terry Morrow, said when crews arrived the flames were leaping metres into the air.

"The impact was intense. It's actually ruptured the fuel tank on the car and that's probably the ignition source to the truck and the car," he said.

Superintendent Craner said a chaplain was also called to the scene to support the emergency service workers who responded.

"My heart goes out and my thoughts go out to the emergency service workers who attended this," he said.

"[They were] doing their day's work and got called to a vehicle accident and [had to] witness something that no ever wants to see."

Appeal for dashcam footage

Superintendent Craner has urged for anyone with dashcam footage of the accident to share it with NSW Police or Crime Stoppers by calling 1800 333 000.

ABC Local radio listener Roger described witnessing the fiery explosion.

"The traffic came to a grinding holt — [I] hit the anchors pretty hard," he said.

"All I saw was this huge ball of flames up ahead engulfing the bridge.

"[There was] a lot of fire and shortly after that police and fire engines arrived and got the fire out reasonably quickly.

"It was quite a huge wall of flames while it was burning."

Southern Region Crash Investigation Unit officers are on the scene and motorists have been advised to avoid the area until further notice.