Hot and dry conditions this weekend will make it difficult for firefighters to extinguish the ongoing bush fire in the Pilliga Nature Reserve. 

As of 9:30am this morning, Saturday 1 March, the fire had burned more than 4600 hectares.

The Sandstone Cave Walking Track and the Newell Highway between Coonabarabran and Narrabri have been closed since 6pm on Wednesday 26 February. 

Traffic can divert via Gunnedah using the Kamilaroi and Oxley Highway. 

"They still have a fair amount of work ahead of them," a Rural Fire Service (RFS) spokesperson said. 

Despite a decrease in fire activity in the morning of Thursday, 27 February, temperatures around 35 degrees during the day contributed to the fire spreading over 2,300 hectares by Friday afternoon, particularly in the north-east corner of the fire.

Stormy weather in the night from Wednesday to Thursday contributed to the spread of the blaze. Photo: RFS NSW Facebook

Currently, there are around 20 firefighters from the RFS and National Parks attending the scene, including out-of-area incident management crew. 

Heavy machinery and aircrafts are being used to control the blaze. 

There is currently no immediate threat to properties. Authorities urge residents to continue to monitor the situation closely over the weekend.