Severe Australian bushfire risk to return next week

[Loretta]

NSW is preparing for the worst with severe bushfire conditions forecast to return next week, as more than 30 fires continue to burn across the state.

Temperatures are again expected to soar past 40 degrees celsius in Sydney and other parts of the state early in the week, says the Rural Fire Service (RFS).

Fire crews will work throughout the weekend to contain as many of the blazes as possible, especially those with the potential to threaten property.

During Thursday's heatwave, a scrub fire in Sydney's north west bore down on homes at Londonderry, but residents worked with fire crews to protect their properties until a southerly change eased the threat.

Although the homes were saved, a number of trucks, cars and sheds were destroyed.

With temperatures down by as much as 10 degrees on Friday, Premier Nathan Rees and RFS chiefs urged residents to prepare for another blast of searing heat on Monday.

"We can expect more hot conditions next week, reaching into the 40s again in western Sydney over the next week or so," Mr Rees told reporters after touring the Londonderry area.

"And that means people that live on the urban and bush interface areas of Sydney ... should take all appropriate precautions."

NSW Rural Fire Service Commissioner Shane Fitzsimmons said on Friday the RFS was battling more than 30 fires sparked by hundreds of lightning strikes over the past two days.

"Fortunately they are being controlled right through the patrolled status, so there is no fire activity causing adverse concern like we saw yesterday afternoon," he told reporters.

The Londonderry fire and another which burnt close to a factory complex at Mount Kuring-gai on Thursday have both been contained and the bushfire emergency declaration for both blazes revoked.

However, Mr Fitzsimmons said crews were closely monitoring a fire at Evans Head on the NSW north coast, which is burning on Defence Force land.

A statement from Defence to AAP on Friday said the fire began after two F-111s did practice bombing runs at the site on Thursday.

The Defence Force said another bushfire at Singleton in the Hunter Valley region, had also started during a live training exercise.

Almost 500 firefighters are working on fires between Evans Head and greater Sydney, as well as in southern NSW and the central west.

Mr Fitzsimmons said there were hundreds of lightning strikes on Thursday night in the central west and central tablelands, Illawarra, south coast, Hunter and Central Coast.

"Fortunately we have no fire impacting on property and causing us concern at this stage, but our focus is on consolidating that containment before we return to the hotter weather next week," he said.

The RFS late on Thursday confirmed that one of two men charged over a bushfire in western Sydney was a former RFS volunteer.

Daryl Byrnes, a former RFS junior member for two years, and another man allegedly set a Holden Commodore alight in bushland on Comleroy Road near Kurrajong, west of Sydney, about 3pm (AEDT) on Wednesday, police said.

The fire spread to surrounding bushland in the Wollemi National Park, causing extensive damage.

They have both been charged with intentionally causing fire and being reckless with its spread, damaging property by fire, and stealing a motor vehicle.

They were refused bail and were due to appear in Blacktown Local Court.