More than 1000 hectares burnt in Pillaga fire, highway remains closed

Firefighters are working to extinguish a forest fire burning west of Gunnedah that has already scorched more than 1000 hectares and closed a major highway.

The fire is burning in the Pillaga National Park near the Sandstone Caves on the Newell Highway, less than 50km from Coonabarabran.

The highway was closed overnight Wednesday due to the fire threat which was still impacting the road late on Thursday afternoon.

NSW Rural Fire Service Namoi-Gwydir district manager Katherine Scott-Dickson said heavy plant equipment is working to establish containment lines in the area.

Also on the ground are six RFS trucks, in support of 10 National Parks and Wildlife Service vehicles involved in the firefighting effort.

Several aircraft are also assisting but predominantly in an aerial intelligence and fire monitoring role.

Ms Scott-Dickson said the fire is not impacting private land but is moving in a north east direction ahead of an expected wind change this evening.

She said small spot fires have been observed within 200 metres of the fire front and at different points along the Newell Highway.

The highway was expected to remain closed overnight Thursday before an assessment is made on Friday morning.

Adding to the complexity is a requirement from Transport for NSW to deem the highway safe for motorists before it is re-opened.

The cause of the fire is unknown but authorities believe its ignition was likely the result of an old lighting strike.

Ms Scott-Dickson explained how grass fires often start on the day of an electrical storm but forest fires can begin up to a week later. This happens when a smoldering tree struck by lightning eventually collapses and ignites dry grass.

She added that fires in the Pillaga can be particularly difficult to contain due to the oil-based nature of pine trees in the area.

To report fires or other emergencies call 000 (triple zero).