Four killed on Victoria's roads

Four people have been killed on Victoria's roads in less than 24 hours, with a cyclist the latest fatality.

A truck crashed into a motorised bicycle on the Henty Highway at Portland in Victoria's west on Saturday afternoon.

The cyclist, an 18-year-old Portland man, died at the scene and the truck driver stopped at the scene. He is assisting police.

It's the fourth death on the state's roads.

A motorcyclist and driver collided with an SUV at Heatherton Rd at Springvale South about 4.45pm. The rider, who has yet to be identified, was critically injured and died on the way to hospital.

Earlier in the suburb of Narre Warren a car turning onto Berwick Road from Wellington Road smashed into an oncoming car.

The driver died at the scene and has not been formally identified.

The pair in the second car, an 18-year-old Belgrave man and his passenger, a 19-year-old Menzies Creek woman have been taken to hospital with non-life threatening injuries.

Just before 3am a car ploughed into the rear end of a parked tray truck at Reservoir and the driver, a man in his 30s, died at the scene.

Another man aged around 30 was taken to hospital with life-threatening injuries.

The deaths bring the state's road toll to 51, compared to 34 at this time last year.