Fire authorities, meanwhile, have confirmed an additional 25 homes have been lost to bushfires in NSW, taking the total number of losses this season to 2400.

The NSW Rural Fire Service says assessments carried out since Friday have revealed an additional 25 homes were destroyed and almost 300 saved in the most recent blazes, taking the housing toll to 2399.

The death toll from the state's unprecedented bushfire season climbed to 25 last week after a man's body was on Friday found in a NSW south coast home.

The 59-year-old man's remains were found in a house in Bodalla, southwest of Moruya, after a bushfire raged through the area on Thursday.

Three US firefighters also died on Thursday when their aerial water tanker crashed northeast of Cooma. The families of the three men are expected to visit the Peak View crash site on Wednesday.

The Bureau of Meteorology, meanwhile, says the fire risk across the most-populated areas of NSW is set to escalate from Friday, with the NSW south coast, southeast regions and ACT likely the worst affected.

Western Sydney could also experience temperatures of up to 45C.

This is because a system of hot air moving south of the Australian continent will help drag hot air across the NSW coast.

"It looks like fire danger is ramping up as we head into the weekend and Saturday will be the peak day again," BOM meteorologist David Wilke told AAP.

Northern NSW will also experience bushfire danger through to Sunday.

The RFS says warm, dry and windy weather has led to a total fire ban being issued for the southern ranges on Tuesday. There's also very high fire danger in the central and southeast regions of NSW.

The body encouraged NSW locals to prepare for tough conditions this weekend.

There are currently more than 55 fires burning across NSW, while a blaze in the Orroral Valley in the Namadgi National Park in the ACT is at emergency level.

The 3000-hectare fire - which is threatening properties on Boboyan, Apollo and Top Naas roads - has not yet jumped across the ACT-NSW border.

There is no current threat to properties in Tharwa or Canberra.

"Leaving immediately is the safest option. Soon it will be too dangerous to drive," the ACT Emergency Services Agency said in a statement.

"The fire may pose a threat to all lives directly in its path."

Shoalhaven City Council urged visitors to return to the south coast to inject some much-need cash back into the local tourism industry.

Shoalhaven Tourism Advisory Group chair Rob Crow said some towns are rebuilding but most remain unaffected directly by bushfires and need help.

"Recovery is a long game and we need our visitors back more than ever," Mr Crow said in a statement on Tuesday.

Australian Associated Press