The semitrailer, which was carrying a generator, was travelling in the northbound lane at about 5.22am, near Thornford Road in Yarra, when it left the road and crashed.

The vehicle careered up a slight embankment beside the highway and travelled for about 100 metres before landing on its driver side in a paddock, police said.

Chief Inspector John Sheehan said the man, who lived in Richardson, died at the scene. He was not treated by paramedics.

It is understood he had family interstate.

Irwin and Hartshorn, which are located in Hume, did not make a comment about the accident. Goulburn police said the trucking company is assisting them with their investigations.

There were no witnesses to the accident, but a passing motorist noticed the Kenworth truck in the paddock beside the highway and notified emergency services.

Chief Inspector Sheehan said the driver was believed to have left Canberra before 5am.

Police Rescue, NSW Ambulance, NSW Fire and Rescue and Roads and Maritime Service responded to the crash and closed part of the highway's northbound lane.

The lane has since reopened and the truck has been towed from the scene.

A forensic team from Queanbeyan attended and a report will be prepared for the coroner.