Heywood police Acting Sergeant Mark McLean said the driver of the B-double was on his way from Portland to Naracoorte to pick up a load of woodchips when he noticed smoke about 4.40pm.

The driver pulled over and grabbed his fire extinguisher, but by then it was too late and the truck was well alight, he said.

Acting Sergeant McLean said an electrical fault sparked the blaze which destroyed the prime mover and caused $180,000 damage.

He said the Lyons fire brigade was able to the extinguish the blaze and prevent it from spreading to the two trailers. 

“The driver pulled over into one of the only spots where it wouldn’t have caused a forest fire,” Acting Sergeant McLean said.

“It’s fortunate it caught fire where it did and when it did.”

He said there were few safe spots to pull over because there were steep drop-offs along much of that section of the road. 

The driver was uninjured and traffic was disrupted on the Princes Highway until about 1pm.