Major Collision Investigation Unit detectives are continuing to investigate the circumstances surrounding fatal collision in Woori Yallock last night.
It is understood a green Holden Commodore and a white Holden Commodore were travelling east along Warburton Highway at Wandin when the cars collided.
It is understood they continued to drive erratically before stopping near the intersection of Elvian Road about 10pm.
The male drivers of both vehicles stopped at the scene.
Police have been told the driver of the green car got back into the vehicle and left the scene.
It is believed the driver of the white Commodore, a 39-year-old Yarra Junction man, stopped and got out to assess the vehicle, before the car rolled and hit him.
He was treated by paramedics but died at the scene.
Police are still seeking the identity of the driver of the green vehicle and urge him to come forward.
Anyone who witnessed the incident, has CCTV, dashcam footage or any other information that could assist police is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au