Fire and Rescue crews responded to a truck fire on the Pacific Highway at 3.30am this morning.
The highway was closed in both directions near Collombatti, 20 kms south of Eungai, and motorists were diverted to Macleay Valley Way.
The B-double's back trailer was fully engulfed by fire when firefighters arrived.
"The driver had disconnected the second trailer to stop the fire from spreading," Kempsey Fire and Rescue station commander Tony Hackenberg said.
A Hazmat unit from Port Macquarie attended as well as Rural Fire Service crews and police.
The truck was carrying parcels, the load in the second trailer was completely destroyed in the blaze.
Firefighters worked for a number of hours to bring the fire under control. It was extinguished at 7am this morning.
One northbound lane re-opened at 9am, with salvage operations continuing.