Screenshot of a video showing an Australian woman Toni Doherty rescuing a koala from a bushfire in New South Wales on November 19, 2019.

Massive bushfires in southeastern Australia still have a "long way to go," authorities have warned, even as colder conditions brought some relief to exhausted firefighters and communities on Saturday.

After a blustery night that saw a series of massive infernos in New South Wales and Victoria merge into a mega-blaze four times the size of Greater London, temperatures dropped and rain fell on fire-scarred regions.

The milder conditions are expected to last around a week, giving firefighters time to try to get the fires under control.

New South Wales Rural Fire Service commissioner Shane Fitzsimmons described the conditions as the "best seven days we have had without a rise of very dangerous fire ratings."

In a matter of months, the catastrophic bushfires have killed at least 26 people, destroyed more than 2,000 homes and scorched some 10 million hectares - an area larger than South Korea or Portugal.

University researchers estimate that more than one billion mammals, birds and reptiles have been killed in the blazes.

Despite the cool change, authorities warned that the bush-fire season is not yet over, with hundreds of fires across several states still raging.

In Victoria, Premier Daniel Andrews called on communities to remain vigilant and warned that the months-long crisis was "a long way from over." 

That message echoed in the town of Mogo, where what remains of the main street was still without power and the few open businesses were running on generators.

On Friday, tens of thousands of protesters took to the streets across the nation's cities, calling on Australia's conservative government to take stronger action on climate change.

A Sydney citizen who preferred not to be named told the Global Times on Sunday that her company hands out anti-smog gauze masks to employees every day owing to the fire.

Scientists say climate change has contributed to the lengthening of the fire seasons and fueled more frequent and intense blazes.

The Australian Academy of Science, an independent organization representing the country's leading scientists, said Canberra "must take stronger action" as part of its global commitments to limit global warming.

"The scientific evidence base shows that as the world warms due to human-induced climate change, we experience an increase in the frequency and severity of extreme weather events," the academy's president John Shine said in a statement.

Australia experienced its driest and hottest year on record in 2019, with its highest average maximum temperature of 41.9 C recorded in mid-December.

AFP - Global Times