A truck driver has died after two heavy vehicles collided and caught fire on the Hume Highway near Gunning early on Friday.

Police say a road train had broken down in the northbound lanes at Breadalbane about 4.10am when it was struck from behind by a B-double carrying aerosol cans.

Firefighters extinguished the blaze, but both trucks were destroyed.

The 31-year-old driver of the road train suffered minor injuries and was taken to Yass Hospital for mandatory testing.

The body of the second driver was later found in the wreckage. Formal identification is yet to take place.

Police have begun an investigation into the crash. The Hume Highway has reopened in both directions under traffic control, with a contra-flow operating past the crash site.

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