Australian firefighters were working to contain a "volatile" bushfire in the southern state of Victoria on Friday, urging thousands of people to evacuate rural areas threatened by the blaze.

The out-of-control blaze, about two hours' drive northwest of state capital Melbourne, has already burned through about 10,000 hectares (24,000 acres) of forest and farmland.

Almost 1,000 firefighters have been deployed to battle the blaze.

"They will be supported by water-bombing aircraft, including the large air tankers, so we are throwing everything we can at it," Country Fire Authority chief Jason Heffernan told national broadcaster ABC.

"I do expect the fire to remain rather dynamic and volatile," he added. "We're not out of the woods yet."

Emergency services have urged thousands of people from 28 rural communities in the path of the bushfire to leave their homes and head towards evacuation centres.

"In this dangerous and difficult time, all Australians are thinking of those working bravely to save lives and homes," Prime Minister Anthony Albanese said in a statement released on social media.

"Our hearts are with everyone facing the fires."

After several wet years, Australia has been facing one of its most significant bushfire seasons since the catastrophic conditions of 2019-2020.

During that so-called "Black Summer", bushfires raged across the country's eastern seaboard, razing swathes of forest, killing millions of animals and blanketing cities in noxious smoke.