Hundreds of thousands of dollars of luxury cars have gone up in flames after a truck carrying BMWs caught fire early on Friday.

When the Jugiong and Berremangra Rural Fire Service brigades responded to a triple-0 call regarding a truck fire on the Hume Highway around 4am, they got to work.

Despite their efforts, the B-double car-carrier laden with the precious European cargo was completely destroyed.

Diversions were established around the fire site on the Hume, just north of Jugiong, as the RFS began the clean-up and detectives initiated investigations into the fire.

Traffic diversions from the Hume Highway sent motorists onto the Burley Griffin Way through Cootamundra and Harden.