A motorbike rider has suffered serious burns to his face and body after an acid attack on a highway near Melbourne.

Police say the 62-year-old victim was riding back to Melbourne on the highway when he was hailed down by another motorbike rider just before midday on Saturday.

The 62-year-old was then reportedly pushed down an embankment by the other motorcyclist, who fled when a green sedan pulled up.

Detective Acting Sergeant Peter Johnston says three men got out of that sedan and verbally abused the victim before throwing a large amount of acid in his face.

"It's an absolute callous attack, there's potential to do some serious injury to this man," he said.

Police say the victim has no links to outlaw motorcycle clubs and there does not appear to be any motive for the attack.