Firefighters warned people on Tuesday to flee or take shelter if it is too late to leave as warm, gusty winds fanned "very challenging" bushfires in Victoria, eastern Australia.

About 650 firefighters were battling fires across 17,000 hectares (42,000 acres), said Jason Heffernan, chief officer of the state's Country Fire Authority.

Wind gusts of up to 80 kilometres per hour (50 miles per hour) were reported around East Gippsland, about 250 kilometres (155 miles) east of Melbourne, he said.

Emergency services issued evacuation orders for nine rural neighbourhoods, saying the fires were "threatening homes and lives".

People who had not yet left from another seven neighbourhoods were told to take shelter immediately because "it is too late to leave the area safely".

"We are experiencing spot fires well ahead of the main fire front and firefighters are doing their best to try and contain that fire but it is very challenging," Heffernan told Australian public broadcaster ABC.

"It is proving to be quite difficult, burning in both private property but also in some pine plantations. So the next couple of hours will remain very challenging for firefighters on the ground."

Rain was expected to help dampen the flames late in the afternoon, he said.

Separately, a bushfire was "out of control" in an area of Flinders Island in Tasmania, the state's emergency services said, although recent rainfall had slowed its spread.

After several wet years, experts are expecting the coming Australian summer to bring the most intense bushfire season since 2019-2020.

During that "Black Summer", bushfires raged across Australia's eastern seaboard, razing swathes of forest, killing millions of animals and blanketing cities in smoke.