Driver fell from Vic truck before fire

A truck driver has died after being thrown from a cement prime mover that collided with a car on a Melbourne road.

Police say the man fell from the prime mover after the collision before the truck and trailer continued down the road, hitting a tree and catching fire.

The long-term employee of Cement Australia was driving the truck out of the company's complex in Port Melbourne when his driver side was struck by a sedan about 5.20am on Friday, Detective Sergeant Mark Amos said.

He said it appeared the truck driver suffered serious injuries as a result of falling from the vehicle.

"The driver of the truck appears to have fallen from the truck at some stage in the collision and landed on the road," Det Sgt Amos told reporters at the scene.

"He was found on the road."

He said the sedan likely ruptured the fuel tank of the truck during the collision.

The truck was completely gutted when it caught on fire after hitting the tree.

The car driver was not injured and is assisting police with their inquiries.

"He's obviously very shocked. He's very upset," Det Sgt Amos said.

"A car hitting a truck, he's very lucky he wasn't hurt, very lucky."

Det Sgt Amos said he had spoken with a colleague of the man who died.

"They've taken the news probably pretty badly. They've lost a colleague," he said.

He said debris such as oil and fuel was spread around the crash site.

Det Sgt Amos said the car driver had returned a negative blood alcohol reading on a preliminary test.