Australia bushfires: Police on the hunt for arsonists who deliberately lit 12 blazes

Police in Australia are on the hunt for arsonists behind 12 bushfires deliberately lit during this week's catastrophic conditions across New South Wales.

More than 1000 firefighters worked overnight to protect properties and establish containment lines for wildfires still raging across NSW and Queensland.

Conditions are expected to worsen during the next few days.

Acting Assistant Commissioner Stuart Smith says tip-offs from the public are flooding in as they work to catch the arsonists.

"We're following up hundreds of incident reports from Crimestoppers; we're still encouraging more," he told reporters.

If caught, the arsonists face up to 14 years behind bars. NSW Premier Gladys Berejiklian says they will be punished if caught.

"The full force of the law will be brought down on them," she said.

Authorities are looking at social media and phone records to help determine who might have been near the fires at the time they started, 7 News reported. 

"It's a pretty despicable thing to do," one resident told 7 News.

People have taken to social media to express their shock at a fireworks display in Sydney amid a total fire ban.

On Wednesday a water-bombing helicopter crashed while fighting bushfires in Queensland.

Emergency services scrambled to the scene, fearing fuel from the aircraft would spark more blazes.

The pilot, in his 70s, managed to escape from the wreckage alive. 

Strong winds are suspected to be a factor in the crash.