Rural Fire Service (RFS) crews from all over the state have been sent to the area to assist the Narrabri crews, from surrounding towns like Baan Baa, Wee Waa, Moree, Gunnedah, Curlewis and Tamworth, to firefighters from the Queensland Fire and Emergency Service and from Queanbeyan near Canberra.

National Parks and Wildlife crews have also come in from around the state, including crews from Jindabyne, as well as Forestry Corporation crews.

Read also:

NSW SES Narrabri Unit and Narrabri Volunteer Rescue Association have been assisting with running the airbase, and delivering vital supplies around the fireground.

RFS public liaison officer Daniel Osborne said there were still no direct threat to properties or assets.

"We have favourable conditions today so we're taking advantage of that and implementing some back burning which will strengthen containment lines for us," Mr Osborne said.

Mr Osborne said conditions were set to deteriorate towards the end of the week, so residents should remain vigilant.

He said locals could receive updates by checking the RFS website, calling the RFS Bush Fire Information Line on 1800 679 737 or using the Fires Near Me app.

Over 13,000 hectares of the park has now been burnt.