The cause of a truck fire that created a traffic debacle on the Western Highway on Tuesday morning remains undetermined.

About 25 firefighters from across Stawell, Joel Joel, Great Western and Dadswells Bridge responded to calls of a truck on fire outside 2542 Western Highway, Stawell at about 11.30pm on Monday night.

The truck was carrying a collection of furniture and stationery with no hazardous material on board.

The driver was able to escape the incident without injury.

"It took some time to extinguish the fire and several hours for the cleanup," CFA district 16 duty officer Owen Tudball said.

"Appliances were at the scene assisting with cleanup until about 10.30am. It had quite a significant impact on the highway.

"At this stage it is undetermined what caused the fire."

A small grass fire also broke out around the truck but was contained and extinguished quickly.

Mr Tudball said a call was made at about 8.30am on Tuesday of another incident on the highway but nothing came of it.

"We had someone call up about the same incident, just about eight hours too late," he said.

"We did inspect along highway but there was definitely no second event."

UPDATE, 8.30am

Traffic is flowing along the Western Highway with just one lane now blocked off along a section of the road near Stawell.

Traffic is being managed between London and Monaghan Road in Stawell, with the cleanup from a truck fire still underway.

Earlier

The Western Highway is closed in between Ararat and Stawell following an incident overnight.

A truck fire early on Tuesday morning forced emergency services to shut the road. The fire is under control.

VicRoads said the alternative route is Pomonal Road and Ararat-Halls Gap Road through Pomonal and Moyston.

The scene will reopen once the truck has been cleared and the road has been repaired. It is unclear how long that will take.

More to come.

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