Swimming snakes are providing extra incentive for Victorians to keep out of floodwaters as parts of the state brace for further heavy rains and possible flash floods.

Some areas of Victoria could receive a month's worth of rain within 24 hours as heavy downpours cross the state.

Flood warnings remain in place in the north, centre and southwest of Victoria. A severe weather warning for heavy rain and possible flash flooding has been issued in the Mallee and parts of the Wimmera, South West, North Country, North Central and Central districts.

One-day totals of 20 to 50 millimetres are forecast in Mildura, Horsham, Bendigo, Maryborough, Kyneton and Ballarat.


Some areas may even be hit with up to 70mm by later this afternoon, the Bureau of Meteorology warns.

But it is not known precisely where those higher totals will be recorded.

The SES is urging everyone to have a plan ready in case they encounter flooding. For drivers who aren't compelled to heed the SES' constant warning to never enter floodwaters, spokesman Stefan Delatovic had a different kind of message.

"In Coleraine we saw snakes in the waters so ... if you don't want to meet snakes stay out of floodwaters," he said.

"If nothing else moves you - just imagine swimming with a snake."

The Age reported that tiger snakes were seen swimming through the streets to escape the rising water.

A major flood warning is in place for the Glenelg River catchment where some homes and businesses were flooded at the weekend.

The Loddon River catchment has a moderate flood warning. There's also a moderate flood warning for the Murray River at Corowa and a minor warning at Albury.