A hit-and-run that killed a cyclist near Geelong may have been deliberate, police have said, after they received numerous reports of cyclists being "stalked" in the area.

Gordon Ibbs, 77, was killed when he was struck by a car on the Geelong-Ballan road at Anakie about 2:30pm on Sunday.

Police said they were looking for the driver of a maroon sedan, believed to be in his 20s.

Detective Sergeant Mark Patrick said the driver would have known he had hit the man.

"Witnesses indicate there's been no attempt by the driver of the vehicle to stop or to avoid the cyclist, and it makes me wonder whether it was actually a deliberate act by this person," he said.

Detective Sergeant Patrick said several people had contacted police to report a car matching the same description harassing cyclists around Geelong earlier this month.

"On the third of May someone was riding home and noticed something prodded from the vehicle, and was concerned it looked like they had been tailgating the pushbike, and then as the vehicle drove past prodded something at the cyclist," he said.

"The second occurrence involved a night-time about 6:00pm in a Geelong suburb, where the vehicle's headlights were actually turned off before the vehicle drove past the cyclist and threw something, striking the cyclist."

"There was no injury to either of the cyclists but there's certainly concern they're being stalked."

He said the car would have been damaged in the crash, and anyone with information should contact Crime Stoppers.

He said Mr Ibbs was physically fit and had worked at Ford until he retired.

"He was a keen rider," he said.

"Would always go out, had a number of road bikes, racing bikes, road bikes, and that was his joy."

In a statement, the Ibbs family said: "Gordon was a beautiful, kind, caring man and he did not deserve this".

"We have heard that witnesses stopped at the time of the accident and we wish to extend our deepest thanks to them for being with Gordon - it really means a lot to us to know he wasn't alone," the statement read.

"While we thank the community for their sympathies and best wishes, we request they respect our privacy at this time."