Traffic in Melbourne’s west has been delayed for hours after a fatal collision on the M80 bypass

Police are searching for a white truck involved in a fatal crash in Melbourne’s west that caused major traffic disruptions on Thursday evening.

A white lorry was traveling on the Altona section of the M80 ring road at around 4pm when a ramp fell off the back of the vehicle.

Investigators believe the ramp crossed the highway and collided with a car traveling in the opposite direction, killing the driver.

The truck did not stop at the scene and was last seen heading towards Altona.

The deceased driver died at the scene and has not yet been identified.

As a result of the collision, major traffic disruptions are expected in the area that will last several hours.

According to VicTraffic, all Greensborough-bound lanes of the M80 bypass are closed between Ballarat Road and Sunshine Avenue.

All traffic will be diverted via McIntyre Road to Ballarat Road to return to the M80 bypass.

Chris Miller of the Department of Transport and Planning said delays could last all night as investigators examined the crash site.

“We do not know how long the closures are likely to remain in place, but experience shows that it will last for several hours,” he said.

“I wouldn’t be surprised if it was still closed at midnight.”

Police are appealing for anyone who witnessed the collision or has footage to contact Crime Stoppers on 1800 333 000 or visit crimestoppersvic.com.au