Australia's bushfires circle Sydney as temperatures soar

Catastrophic conditions fuelled massive bushfires across Australia's New South Wales State on Saturday, with two blazes around Sydney burning at emergency level, while in South Australia one person was found dead in a fire zone.

Some major roads heading to the south and west from Sydney were closed for part of the day and authorities asked people to delay travel at the start of the Christmas holiday period, warning of the unpredictability of the fires due to high winds and temperatures above 40C (104F).

A cooling but powerful wind with gusts of up to 90 kmh (56 mph) from the south swept through the state late on Saturday, lowering temperatures significantly but also creating risks that the winds could spread the flames and embers.

"Today has been an awful day," NSW Rural Fire Services Commissioner Shane Fitzsimmons said of the conditions which were rated "catastrophic", the highest level of danger.

Fitzsimmons said conditions in Sydney may not have reached forecast catastrophic levels, although they did elsewhere.

He said the haze from the fires that has choked the city in recent weeks might have helped cap temperatures on Saturday by acting as insulation.

By early evening, six fires in the state were rated at emergency level, including two around Sydney.

"We have seen property impacted and lost. We have 3,000 firefighters and emergency services personnel out there dealing with the fires," Fitzsimmons told a media conference.

Media reported one person was unaccounted for near Lithgow, a town about 140 km (85 miles) west of Sydney where a number of properties were burned.

Close to 100 fires were burning across NSW, and the RFS said some fires were generating their own thunderstorms.

Conditions were expected to improve in coming days, before another burst of hot weather in about a week.

"We will not get on top of these fires until we get some decent rain - we have said that for weeks and months," Fitzsimmons said.

No significant rainfall was expected in the next couple of months, the Bureau of Meteorology said.

The Gospers Mountain mega fire has already burned almost 460,000 hectares (1.14 million acres) to the northwest of Sydney, and there was a risk it could join up with the Grose Valley fire in the Blue Mountains to the west of Sydney.

The death of the two firefighters on Thursday night, when a tree fell on their truck as they drove through a firefront, brought the death toll from the NSW wildfires to eight since early October.

Shortly after the two deaths were announced, Prime Minister Scott Morrison said he was rushing back from a family holiday in Hawaii, a trip that had drawn sharp criticism as the crisis deepened. He was expected to arrive later on Saturday.

In South Australia, authorities said one person had been found dead, another was critically injured and 15 homes had been destroyed by a fire in the Adelaide Hills, just 40 kilometres (25 miles) east of the state capital of Adelaide.

The death followed another fatality in South Australia on Friday, the result of a car crash which sparked a fire.

Authorities said fires had burnt through some 40,000 hectares in the state and 23 firefighters suffered injuries on Friday.

In Victoria, authorities said 142 fires had started in the state since Friday, with one burning at an emergency level late on Saturday afternoon.

Australia has been fighting wildfires for weeks, with blazes destroying more than 700 homes and nearly 3 million acres (1.2 million hectares) of bushland.