Scores of Australians have evacuated their homes in mountains west of Sydney as intensifying winds fanned wildfires that have ravaged the region for days.

The winds are showering communities with embers and all schools were closed in anticipation of worsening conditions in the Blue Mountains. The region lost more than 200 homes to blazes last week.

Rural Fire Service commissioner Shane Fitzsimmons said 71 fires are burning in New South Wales state around Sydney, including 29 which are out of control.

Authorities advised Blue Mountains residents who were not prepared to defend their homes from fire to leave for evacuation centres in Sydney, or Lithgow to the west. One centre in west suburban Sydney was housing 120 evacuees.

About 3,000 firefighters, including 1,000 out-of-state reinforcements, were battling the blazes.

Mr Fitzsimmons said: "Whatever unfolds throughout the afternoon today, there will still be a lot of fire edge that firefighters are going to have to continue to deal with through tomorrow, the coming days and coming weeks."

A total of 95 firefighting aircraft were deployed, but winds up to 50mph forced the water-bombing helicopters to suspend operations over fires at Lithgow and the Blue Mountains during the day, Fire Service spokesman Ben Shepherd said.

Temperatures in the fire zones rose above 32C, and weather conditions were forecast to be the worst since last Thursday, when many of the homes that burned last week were lost. One death has been blamed on the fires.

The early start to the fires this year "is indicative of the unseasonably hot, dry conditions that have been building now throughout winter into spring, and we need to remind ourselves that we still have a long way to go as we look down the coming months into summer", Mr Fitzsimmons said.

Springwood resident Rae Tebbutt said the atmosphere was tense in the village that was one of the worst-hit last week.

"Everyone is terrified," she said. "I've got three friends who have lost everything."