The driver of a white van, who has not yet been formally identified, ran into the back of a stationary truck about 1pm at the Queen Street traffic lights.

Despite attempts to resuscitate him, the man died soon after being pulled from the van.

The man was the sole occupant of the van.

The driver of the truck was not injured, and police at the scene said they are appealing for dash-cam footage.

"We're investigating whether a medical episode contributed to the cause of the collision, however that is still under investigation," Ballarat Highway Patrol's Sergeant David Whitwell said.

"The truck driver remained at the scene and is assisting police with enquiries, he'll be interviewed at a later stage as a potential witness.

"That's part of our normal process, there's no indication at this stage of any fault or culpability on his part."

He added the coroner will be investigating the cause of the crash.

The scene was quickly cleared, with a notification about Victoria Street reopening to Melbourne-bound traffic sent at 3.36pm.

Anyone with information, or dash-cam footage, is urged to phone Victoria Police on 1800 333 000.

If you are seeing this message you are a loyal digital subscriber to The Courier, as we made this story available only to subscribers. Thank you very much for your support and allowing us to continue telling Ballarat's story. We appreciate your support of journalism in our great city.