The mercury in Tamworth is set to hover around the 40-degree mark for much of the next week as a heatwave bakes the region.

The RFS declared total fire bans for Friday in the Northern Slopes and North West areas meaning all open fires are prohibited and fire permits have been suspended.

It’s got local fire crews on alert, and already firefighters are enduring hot conditions to fight a massive bushfire burning in the Pilliga forest.

The blaze was sparked at about lunchtime on Wednesday and had burnt more than 7640 hectares of bush land by Thursday afternoon.

Smaller local planes were used to help dump water on the fire, with a larger aircraft from Sydney also deployed to lend a hand to efforts to contain the blaze.

North West RFS Superintendent Michael Brooks said the fire was creating a large plume of smoke that could be seen from as far away as Mullaley.

“It is hanging heavily overhead and we suggest anybody with respiratory problems should try to remain in doors as much as possible,” he said.

The Bureau of Meteorology (BOM) is predicting a hot weekend with temperatures to exceed 40 degrees celsius, conditions which, Superintendent Brooks said will not help firefighters.

“The expected upcoming weather conditions could be challenging,” he said.

“We want to encourage everyone to practice good fire safety, have a fire plan ready and to be aware of current fire conditions near them.”

For the Tamworth area, crews are restoring trucks and repairing machinery after weeks of call-outs.

“Lighting strikes have smashed us, the weekend of the 16 and 17th December we had 30 odd jobs, lighting strike after lightning strike,” RFS Inspector Steve Prior said. 

“But we'll be in a heightened state of readiness in preparation for the forthcoming weather conditions.” 

He said crew were monitoring one fire at Scrub Creek, at the back of Hanging Rock, which had been burning for a month.

“It’s so inaccessible, we've had remote aerial bombers bomb it, and then hand teams on the ground chipping trails, and drip torches to burn little pockets out.

“Despite getting eight millimetres and then 23mm of rain on it, it's still going.”

He said teams of firefighters were “recovering now, the last week has been a bit of respite for them”, but the weather conditions didn’t look good.

“We're just basically getting the fleet back up and running again,” Inspector Prior said.