A cyclist was among three people killed in three separate motor vehicle accidents within a two-hour period in Victoria on Monday.

The cyclist died after being hit by a garbage truck in Melbourne's south.

Victoria Police said the male cyclist and truck were involved in a crash on the Moorooduc Highway, near Mornington, about 10:40am.

The man died at the scene.

The garbage truck could be seen amongst trees beside the highway.

Police said the male truck driver stopped and was helping police with their inquiries.

Later on Monday, a man was struck and killed by his own vehicle at Hopetoun Park, north-west of Melbourne.

A Victoria Police spokeswoman said the incident occurred on a dirt track under the Djerriwarh Creek bridge on the Western Freeway about midday.

The spokeswoman said police had been told the driver, a 28-year-old Melton man, was driving up a steep incline when a trailer he was towing became detached from his vehicle.

The driver reversed his Mitsubishi Delica back down the track and got out to reattach the trailer.

Police believe the vehicle slide down the track before hitting the driver and killing him, the spokeswoman said.

A passenger in the vehicle was not injured.

The truck was seen crashed into trees at the side of the road. ( ABC News )

Also on Monday, a motorcyclist has died after a crash involving a car at Heathcote, in central Victoria.

The crash happened on the Northern Highway at Ladys Pass about 11:15am.

The motorcyclist, believed to be in his 50s, died at the scene.

Emergency services treated the occupants of the car, two women in their 60s, for shock.

Police said the latest deaths brought the number of lives lost on Victorian roads this year to 94, compared with 109 at the same time last year.