Tens of thousands of Australians were poised to flee their homes in the country's southeast Monday as worsening floods inundated at least 300 houses, officials said.

Wild storms lashed Victoria state over the weekend, triggering landslides, knocking out power supplies and forcing hundreds of people out of their houses, with many rivers yet to reach their peak.

At least 53,000 people had been put on evacuation alert across the state since the emergency began, officials said, with around 4,000 calls for help from people stranded in their homes or hit by the surging waters.

"We've had around 300 homes that have been affected by floods over the weekend," a State Emergency Service (SES) spokeswoman told AFP.

Residents had been forced to flee in 11 towns, including some which were hit by a devastating firestorm last year, and the SES said more than 100 homes were under direct threat of flooding Monday.

Anthony Griffiths, mayor of the northern Victoria town of Wangaratta, said it was the area's worst flooding since 1998 and it could rival record floods in 1993.

"There are a few variables. The amount of snow melt, and extra rain obviously too, could make things a bit more interesting," Griffiths told ABC radio.

Soldiers joined relief efforts in the worst-hit areas and the SES said emergency crews had come from neighbouring states to boost rescue team numbers.

"We'd hope after tomorrow it should be very much going into recovery mode, but it will depend on the weather for the rest of the week," the SES spokeswoman said.

Officials have warned that it could take several days for raging rivers in the state's northeast to empty, threatening towns further south.

"Where the water has been there is a certainly a massive clean-up for people," said SES chief Stephen Warren.

"As the water travels down into other communities, they are bracing themselves for the impact of that water," he told ABC.

Gale-force winds also lashed the neighbouring states of South Australia and New South Wales over the weekend, felling trees, tearing roofs off homes, and cutting power to tens of thousands of people.