Northbound lanes of the Pacific Highway at Bulahdelah will be closed until this afternoon so a B-double truck that caught fire overnight can be removed.
Motorists are being diverted via Bulahdelah Way to the Lee Street roundabout to return to the highway.
The diversion is suitable for all vehicles while southbound lanes remain open.
Motorists are advised to exercise caution and allow extra travel time.
Rural Fire Service (RFS) crews from Bulahdelah, Wootton,Tuncurry and Pindimar/Tea Gardens were joined by Fire and Rescue NSW firefighters at the site about 7.30pm on Thursday, January 10.
The highway was closed to traffic in both directions as the crews battled the blaze.
As high voltage power lines were in the vicinity of the fire, Essential Energy was called to shutdown power in the area.
The truck was completely destroyed while the driver escaped uninjured.
Crews left the site at 4.30am on Friday, January 11.
A cause of the fire is still to be determined.