Photo taken on Feb. 9, 2020 shows the Harbour Bridge in rain in Sydney, Australia. (Xinhua/Bai Xuefei)

Torrential rain across Australia's east could extinguish all remaining bushfires in the country's most populous state by the end of the week, authorities said on Tuesday, raising hopes a deadly national crisis is almost over.

Australia has been battling hundreds of blazes since September in an unusually prolonged summer wildfire season that was fueled by three years of drought, which experts have attributed to climate change.

Heavy rain and storms have in recent days swept across New South Wales (NSW) state, which bore the brunt of a crisis that engulfed several states and territories at its peak.

The downpour has already doused two of the biggest and longest running blazes and NSW officials are hopeful that more rain forecast for this week will extinguish the remaining 24 fires, four of which are burning "uncontrolled."

"All going well, all will be contained and we're hopeful to get to a stage where we can call them out," the NSW Rural Fire Service (RFS) said in an emailed statement.

The current situation is a far cry from the height of the crisis in early January when NSW firefighters were battling almost 150 fires that produced a firefront about 6,000 kilometers long.

Blazes across the country have razed nearly 12 million hectares of tinder-dry bushland, killing 33 people and an estimated 1 billion native animals, since September. The fires destroyed thousands of homes and prompted mass evacuations of both locals and tourists under apocalyptic-like red skies during Australia's peak summer holiday period.