Bushfire aircraft crashes in NSW

A fixed wing firefighting aircraft carrying one person has crashed on the NSW south coast.

Steve Leahy of the Westpac Rescue Helicopter said rescue helicopters are on the way to the crash scene near Budawang National Park west of Ulladulla.

It's been reported that the plane is an 802 waterbomber being used by the Rural Fire Service and that a wing snapped off before the crash.

The South Coast Register says the plane had been responding to the Wirritin fire in the national park when it went down about 10.30am (AEDT) on Thursday.

The NSW National Parks website describes Budawang National Park as rugged and isolated, full of steep mountainsides and tall moist forests.

A spokesman for the Australian Transport Safety Bureau said the plane was a single turbo prop agricultural aircraft.

He said it is believed to have crashed near the Clyde River.

Key points from the latest RFS briefing:

• Still 66 fires, 24 uncontained
• Four fires at Watch and Act
• Still expecting strong winds today, challenging firefighters in the Blue Mountains area
• The Commissioner has thanked firefighters for their efforts over the last few days but warned there's many months worth of work ahead
• The Commissioner has also thanked the employers of volunteers, including those volunteers who are self-employed

The federal government says it's taking very seriously reports that a training exercise by the Australian Defence Force was responsible for sparking a massive NSW bushfire.

An investigation by the Rural Fire Service has found explosives training on army land at Marrangaroo on October 16 was responsible for starting the State Mine bushfire.

The Department of Defence says it's aware of the allegations and is conducting its own investigation, and will cooperate fully with NSW authorities.

The devastating State Mine fire has burnt through more than 46,000 hectares, engulfing an area from Lithgow along the northern edge of the Blue Mountains, threatening homes and lives.

Acting Defence Minister George Brandis says he's spoken to the Acting Chief of the Defence Force, Air Marshal Mark Binskin, about the matter.

"The Australian government and the Australian Defence Force take this issue very seriously and continue to fully cooperate with the New South Wales authorities, including the New South Wales Police, who are investigating the fire," Senator Brandis said in a statement.

He's extended his thoughts and prayers to the people of NSW affected by the fires, and says the federal government is doing "everything it can" to help NSW authorities bring the blazes under control.

Blue Mountains mayor Mark Greenhill says the fires have done significant damage to his community and has demanded an explanation from the army as to why the explosives exercise went ahead on a dry and windy day.

Mr Greenhill said even though there was no fire ban on the day, the explosives exercise should not have gone ahead.

"I would have hoped on a day like that which was a dry day, a hot day, with the winds - the Australian military would have known it wasn't a good time to be igniting," he said.

"The fire has caused great concern to my community, its done damage to my community and it just shouldn't have happened.

"It's the damage it does to the community and the stress it causes. There's the damage it does in terms of the risks taken by the firefighters, there's the damage it does in terms of the costs to the community of fighting the fire.

"And it's still going."

Defence said in a statement late on Wednesday is was "aware the NSW Rural Fire Service is of the view" the State Mine Fire was caused by a live ordnance exercise at Marangaroo and repeated it was still conducting its own investigation.

"Defence continues to co-operate fully with NSW authorities investigating the State Mine Fire, including NSW Police Force investigators who will prepare a report for the Coroner outlining the full circumstances surrounding the fire," it said.

"Defence is also conducting an inquiry into the circumstances surrounding this explosive ordnance training activity.

"Our thoughts are with everyone currently affected by the fires burning in NSW, particularly those who have had properties lost or damaged in the State Mine Fire."

According to the RFS website, the State Mine fire has destroyed three homes and seven outbuildings.

A Watch and Act alert is still in place for the blaze.

Mr Fitzsimmons said the Defence Department had been open about the fact they may have had started the blaze.

"I don't think anybody is shying away from how this fire started," he said.

"What we did do was an investigation to confirm the speculation that was around early on last Wednesday.

"Our investigation was simply a gathering of the facts, where did the fire start, how did it start - end of story."

Defence said it was still conducting its own investigation.

NSW Premier Barry O'Farrell said it shouldn't be forgotten that the defence department had also provided a lot of firefighting assistance.

"I want to ensure that this doesn't detract from the efforts that defence have made over the past week in assisting the state's emergency services battle these fires," he told the Seven Network.

Communities and fire fighters feared the worst on Wednesday with extreme fire conditions placing pressure on major bushfires burning in the Blue Mountains and Southern Highlands.

However, Rural Fire Service Commissioner Shane Fitzsimmons said the risk had been averted.

BUSHFIRES 'STILL A RISK' IN SOME AREAS

A southerly change swept through the fire grounds on Wednesday night and all bushfires initially subject to emergency alert warnings were downgraded to watch and act.

The southerly winds will contribute to a drop in temperatures, but the winds will be between 45-50km/h on Thursday.

There will be gusts up to 90km/h across the mountain ranges and humidity will be between 10-15 per cent, RFS says.

"We are expecting those winds to be very strong and particularly dry," Mr Fitzsimmons said late on Wednesday.

"While the temperatures will moderate down into the 20s, a welcome relief to what we saw (Wednesday), they still will be strong.

"It's going to be particularly problematic for firefighters because there is no moisture in this change and it is going to be very dry air."

Mr Fitzsimmons said the wind change had a potential to present new challenges for Yarramundi Valley and Grose Valley communities as well as for the northern end of the Springwood fire.

Overnight, fire fighters in the Blue Mountains were carrying out 15-20km of back burning.

More than 20 schools in at risk areas will remain closed on Thursday.

TAFE campuses at Katoomba and Wentworth Falls in the Blue Mountains will also be closed.

Watch the latest RFS media briefing below: