SYDNEY: Firefighters battled to contain nearly 150 fires burning in New South Wales state on Friday as strong winds fanned the flames and again shrouded Sydney, Australia's biggest city, in hazardous smoke.

Bushfires have killed at least four people and destroyed more than 680 homes since the start of November. Fires are still burning in New South Wales, Victoria, South Australia and Queensland states.

While nearly 150 blazes were alight across Australia's east coast, New South Wales Rural Fire Service Commissioner Shane Fitzsimmons said authorities were particularly concerned about eight fires now at emergency levels around Sydney, the state capital where about 5 million people live.

"They have the potential or are expected to spread further east, which unfortunately is getting into more populated areas, villages, communities, isolated rural areas, and other farming practices and businesses throughout the region," Fitzsimmons told reporters in Sydney.

Several fires to the northwest of the city had joined together to create one massive blaze, spreading with hot, dry winds, he said.

Bushfires are common in Australia, but this year's fire season has begun much earlier than usual, with temperatures soaring regularly above 40 degrees C (104°F) before the start of the southern summer and high winds scouring the drought-parched landscape.

Australia’s worst bushfires on record destroyed thousands of homes in Victoria in February 2009, killing 173 people and injuring 414 more.