Police believe a small and a large truck were travelling eastbound on the Western Highway outside Armstrong about 12.30pm when the large truck allegedly rear-ended the smaller truck, pushing it onto the opposite side of the road.

The smaller truck collided head-on with a Toyota Kluger travelling westbound, before a B-double truck driving behind the Kluger hit both vehicles.

The fifth car involved in the crash collided with the stationary vehicles post-collision.

The driver and front seat passenger of the smaller truck, and the driver of the Kluger, died at the scene.

Detective senior sergeant Paul Lineham said police would investigate all lines of enquiry to determine the cause of the crash, including road conditions, speed, fatigue, distraction and impairment.

“It’s absolute carnage down there. We’ve got a truck, a B-double on the side, we’ve got multiple cars involved in there and we’re now sorting through as to exactly what happened,” Lineham said.

“Over the last three weeks it’s pretty much been carnage on Victorian roads. 

“As a lead up to our King’s Birthday long weekend we just implore drivers to pay attention to the roads.

“If you want to have a drink, don’t drive. Don’t get distracted. Take your time to get to your destination.”

Two people were taken to hospital.

Police remain on scene, where the highway is expected to stay closed in both directions between Ararat and Great Western until tomorrow morning.

Motorists are advised to detour through Moyston using Ararat-Halls Gap Road and Moyston-Great Western Road.

The detour will add an additional 20 kilometres to motorists’ journey, so drivers are urged to allow for plenty of extra time.