10:15AM UPDATE: BOTH south-bound lanes of the Hume Fwy are closed after fatal truck crash at Violet Town.
Police say the crash happened about 4.30am when an Australia Post B-double truck ran off the freeway and smashed into a tree.
The truck burst into flames and the driver, who was the only occupant of the truck, died at the scene.
Police will prepare a report for the coroner.
Both south-bound lanes of the Hume Fwy have been closed between Benalla and Violet Town.
Traffic is being detoured off the Hume Freeway onto the Midland Highway at Benalla.
VicRoads says Melbourne-bound traffic should use the Midland Highway, Maroondah Highway and the Melba Highway or Midland Highway and the Goulbourn Valley Highway via Shepparton.
More details as they come.