Sydney fringe on fire alert

A New South Wales firefighter battling fires in Sydney last month. File photo / AAP

SYDNEY - A lethal combination of soaring temperatures and high winds gave the New South Wales bushfire season a vicious jolt with more than 80 fires raging across the state.

A number of properties have been destroyed and casualties are starting to mount with at least four people badly burnt.

A 60-year-old man suffered burns to 36 per cent of his body battling a blaze that destroyed buildings near Albury, while two others were airlifted to Canberra Hospital with burns caused by a fire at Michelago, near Cooma.

At Londonderry, in Sydney's northwest, several residential streets remain under direct threat from a fast-moving bushfire, the Rural Fire Service reported.

The RFS said there were unconfirmed reports of one residential building destroyed in the Londonderry fire, while a number of sheds and outbuildings in the area had also been lost.

Fire authorities said temperatures that soared into the 40s and blustery winds were the trigger.

"That elevation in temperatures and particularly wind has really been problematic for firefighters," RFS Commissioner Shane Fitzsimmons told the Seven Network.

"We have had indications of a house lost at Londonderry - we are still waiting to confirm that.

"Further south in the state we have a very serious fire burning north of Albury affecting places around Gerogery and we've got reports of houses burning in that area as well."

The Ambulance Service of NSW said the 60-year-old man seriously injured at Gerogery had apparently fallen while fighting a fire on his property. He was rushed to Albury Base Hospital.

At Michelago, the Southcare Helicopter picked up two casualties and flew them to Canberra Hospital, while medics attempted to access a third person suffering burns as a 150ha blaze threatened three properties.

Three people were treated for dehydration, smoke inhalation and anxiety at Londonderry, the ambulance service said.

More than 200 firefighters are battling fires directly impacting on several streets in Londonderry where the temperatures topped 42 degrees.

- AAP