SYDNEY Less than 24 hours since residents in parts of Australia's Victoria state fled bush fires, state authorities are now warning of flooding as heavy rain douses flames and lifts rivers in the southeastern state.

Flash flooding is expected through Wednesday afternoon in northeastern Victoria, according to the Australian Bureau of Meteorology, as rain drenched parts of the state where as recently as yesterday, around 17,000 hectares were ablaze.

First responders overnight rescued a farmer in the area who got trapped after driving through floodwaters, according to chief officer operations Tim Wiebusch at Victoria state emergency service.

Parts of the state had received up to 150 milliliters of rain, almost eight times the state's average in September, with more expected today, he added.

"Fortunately we have seen some rainfall across those two fires," said Wiebusch.

"But over these next 24, 48 hours, flash flooding, riverine flooding is really the key risk. We can't emphasise enough, people need to be alert to their conditions."

The rain comes during an unseasonably dry start to Australian spring, which began in September. Last month, was the driest September on record, according to the Bureau of Meteorology, with rainfall 71% below the 1961-1990 average.

Firefights are still working to contain bush fires in two parts of Victoria state but authorities said there was no immediate threat to nearby residents.

Across the border in New South Wales state, a 5200 hectare bush fire burned out of control near the town of Bermagui, roughly 300 kilometers (186 miles) south west of Sydney.

State fire authorities said conditions eased overnight although several properties were lost and firefighters still worked to contain the blaze.

(Reporting by Lewis Jackson; Editing by Aurora Ellis)