All schools had been closed in the Blue Mountains in anticipation of bad fire conditions and authorities advised residents who were not prepared to defend their homes to leave. One evacuation centre in suburban Sydney was housing 120 evacuees.
Seventy-one blazes were burning in New South Wales state around Sydney, including 29 that were out of control, a spokesman for the Rural Fire Service said.
As the temperatures and winds dropped, the danger of fire spreading eased with no reports of injuries or property loss.
Mr Fitzsimmons said many hours of firefighting were ahead but added: "The broader risk to a much larger, more widespread population has certainly eased."
Temperatures in the fire zones rose above 32ÚC and winds blew up to 50mph, forcing water-bombing helicopters to suspend operations during the day.
Springwood resident Rae Tebbutt said that the atmosphere was tense in the village that was one of the worst-hit last week, when 200 properties were lost to the blazes that also caused one fatality.
She added: "Everyone is terrified. I've got three friends who have lost everything."