Fire has been contained on the Sandstone Cave Walking Track and traffic is open on the Newell Highway again.

It took five days of hard work by the Rural Fire Service (RFS) and National Parks to contain the blaze, which kept the Highway closed until this afternoon.

Fire broke out Wednesday at 3:40pm, around 40 kilometres northeast of Coonabarabran and quickly spread due to heavy winds and dry conditions.

The highway was closed on Wednesday at 6pm between Coonabarabran and Narrabri as a safety measure.

A spokesperson for the RFS said that the possibility remained for the highway to be closed again should the conditions change. The fire is yet to be brought under control.

"We ask drivers to proceed with caution and be aware that RFS, National Parks, and Transport NSW volunteers are still on the ground," the RFS said.

The crew are consolidating containment lines in the northwest and northeast of the fire with support from aviation, heavy plant machinery, and specialised tree felling personnel. 

Heavy machinery assists with containing the blaze. Photo: Rural Fire Service.

As of mid-Monday the fire spread to over 5,431 hectares and is still being controlled. 

Seventy crew members, both local and out-of-area, remain at the scene. 

The RFS held an information session on Monday between 11am and 1pm at the Coonabarabran Post Office to answer the questions of any concerned residents. 

Forty-two residents and nine travellers turned up to get the latest updates. 

Another information session will be held tomorrow at the Coonabarabran post office between 1pm and 3pm. 

On Saturday, the fire escaped the containment lines and jumped back over the Newell Highway. Firefighters have since contained the breakout. 

The fire does not pose any immediate threat to properties. Residents are advised to continue to monitor the situation closely. 

"We'd like to thank the local community for the ongoing support and ask that they stay up to date on Hazards Near Me app, local radio, the RFS website, and the RFS Facebook page and be prepared to act should the situation change," the RFS spokesperson said.