Victorians have been reassured that a fatal shooting on a Melbourne freeway was not a random attack, after a man's body was found inside a bullet-ridden van.

Victorian Police say the man was shot to death in a targeted attack and not at random on the city's eastern freeway. He was was found in a white van on the Eastlink freeway at Donvale about 2.20am on Saturday.

It was a "targeted attack" and the public should not be concerned for their safety, Detective Acting Inspector Peter Trichias told reporters on Saturday.

"I want to reassure the public that the shooting itself does not appear to be random, it appears to be a targeted attack," he said.

It is understood the van was moving at the time the victim was shot, in or around the Mullum Mullum tunnel.

Det Insp Trichias would not say whether the deceased had crime links but said there was "no indication" the shooting was in retaliation for another incident.

There were no descriptions of suspects available but police believe more than one person was involved.

Detectives were also combing scenes at Mooroolbark and Bayswater where two dumped cars were found that may be linked to the shooting.

A burnt-out car was found dumped at Mooroolbark about 2.40am, and a grey ute was found abandoned in the middle of Mountain Highway near Scoresby Road at Bayswater about 3.30am.

Offenders involved in the shooting are believed to have dumped the ute in Bayswater before fleeing through a nearby park.

The firearm involved in the shooting had not been recovered late on Saturday night.

Witnesses have been urged to come forward if they saw anything suspicious in the area.