Firefighters were racing to tame an enormous blaze in southeastern Australia on Monday with officials warning it could merge with others to create a mega-fire if weather conditions worsen.

Crews have been battling fires that flared in high winds and searing heat across New South Wales last week with more than 200 homes destroyed so far and many others damaged.

While dozens of blazes have been contained, 58 were still alight and 14 out of control, enveloping Sydney in a thick, white smoke that prompted warnings for people to stay indoors and avoid exercise.

The main concern on Monday was near Lithgow, west of Sydney, where a huge fire that has already burned nearly 40,000 hectares was threatening the communities of Bilpin, Bell, Clarence and Dargan.

Officials fear intensifying heat and winds on Tuesday and Wednesday could push it into another blaze at nearby Mount Victoria in the Blue Mountains and then move it toward the populated areas of Katoomba and Leura.

"I don't think I've ever used the word mega-fire," said New South Wales Rural Fire Service Commissioner Shane Fitzsimmons.

"But the reality is that ... there's every likelihood that in the forecast weather conditions that these two fires, particularly up in the back end of the mountains, will merge at some point."

Firefighters spent Sunday night and much of Monday building containment lines to try to prevent this, ahead of a predicted deterioration in weather conditions.

Another major fire around the Springwood area of the Blue Mountains, where nearly 200 houses were destroyed last week, escalated to emergency-declaration level along with another in Wilton, southwest of Sydney.

"The fire grounds remain dynamic and challenging for firefighters and are particularly susceptible to the wind and the elevated temperatures that we are experiencing," Fitzsimmons said.

But he played down earlier suggestions that all communities in the Blue Mountains, where 76,000 people live, could be evacuated.

"We are not planning a mass evacuation of the Blue Mountains community," he said.

Instead, authorities are taking "a very targeted approach to securing and protecting all the communities".

An emergency warning was issued for the Blue Mountains village of Bell, where residents were urged to evacuate. Other township residents were told to take shelter in their homes or warned that they face several days of isolation without electricity.

This includes people in the village of Mount Wilson, which was used as the backdrop for scenes in the recent Hollywood blockbuster The Great Gatsby starring Leonardo DiCaprio.

Amid the worst fire disaster in the state for nearly 50 years, New South Wales declared a state of emergency on Sunday, which gives firefighters the power to forcibly evacuate people, with penalties for refusing.

The state's Emergency Services Minister, Mike Gallacher, said every possible resource is being used, including firefighters drafted in from other states, with the option that the military could be deployed.

With hundreds of people evacuated due to the encroaching flames, police said they are dealing with reports of looting from victims, although the number of incidents is small.

Agence France-Presse

A firefighter lights a back burn in the Blue Mountains in New South Wales, Australia, on Monday, as volunteer fire brigades race to tame an enormous blaze. William West / Agence France-Presse

(China Daily 10/22/2013 page11)