Australia merges major blazes to manage infernos

Teams of largely volunteer fire crews worked through the night along trails and tracks in heavily forested areas west of Sydney to try and prevent them becoming one dangerous "mega-fire" and potentially racing towards a third blaze nearby.

Firefighters have been battling wildfires across the state of New South Wales since they flared in high winds and searing heat last week, with more than 200 homes destroyed so far and many others damaged.

In the state's worst fire emergency in almost 50 years, dozens of blazes have been extinguished or contained but 62 are still alight and 13 of them out of control, with the Blue Mountains, a popular tourist area, the main focus of attention.

NSW Rural Fire Service Commissioner Shane Fitzsimmons said the two fires "have been deliberately and tactically joined" through backburning efforts.

"That is principally focused on trying to stop those two fires coming together and joining with the fire down at Springwood and Winmalee," he said, referring to a blaze that razed 200 houses last week and which has flared again.

"We are seeing positive results of these very deliberate, very targeted, very decisive strategies being deployed particularly in relation to backburning operations."

But while firefighters -- 1,100 worked through the night, aided by 84 fire-bombing aircraft -- have had "some extraordinary success", he warned "there's still a way to go".

The decision to merge the edges of the infernos near Lithgow and Mount Victoria in the Blue Mountains is designed to destroy the land in a managed way, depriving the fires of the fuel that would otherwise have allowed them to merge uncontrolled.

New South Wales has not seen rain in weeks and the bold strategy came with temperatures and winds expected to pick up later Tuesday and into Wednesday, with lightning also a growing worry.

"We can expect to see those winds strengthen up to 60 (37 miles) to 90 kilometres per hour, which is what we're trying to prepare for and brace for," said Fitzsimmons.

While claiming some success, authorities said the Lithgow area fire continued to threaten properties near the township of Bell, and was burning near the villages of Mount Irvine, Bilpin, Hartley Vale, Dargan and Clarence, with residents urged to leave.

In addition to the fires west of Sydney, large tracts of the state remain at risk and under total fire bans, officials said.