One south-bound lane of the Princes Highway opposite the BTU Road turnoff remained closed at 8.45am, with a 40km per hour speed limit in place for the remaining southbound lane.

A NSW Fire and Rescue media release said they were called to the Nowra Hill scene shortly after 6am on Friday, July 17.

"Crews arrived a short time later and discovered a b-double truck well alight," the release said.

"Firefighters were able to quickly extinguish the blaze however the truck was severely damaged.

"Fortunately the driver of the truck managed to safely evacuate and was uninjured."

Three Hazmat vehicles and the burnt out truck were still there shortly before 9am.

A damaged car that appeared to be a yellow Mustang was also at the scene, loaded onto a tow-truck.