Mandatory evacuations have been ordered for the 2000 residents of the southern Queensland town of St George as authorities predict a record flood.
The Balonne River is expected rise to 14 metres by Monday evening and to peak at up to 15 metres overnight on Tuesday.
The ABC reports residents are being told to leave town via the Moonie Highway before it is closed later on Sunday evening.
Air evacuation to Brisbane is being organised to ensure evacuations can continue after the Moonie Highway closes.
Queensland Premier Anna Bligh flew into the town on Sunday morning and met with local disaster coordinators.
She has urged people to evacuate the town while they still can.
St George mayor Donna Stewart says 20 homes were inundated when the town flooded in 2010 but she expects the damage will be worse this time.
Meanwhile, further north in Charleville flood levels are continuing to drop slowly, where levees have so far held back the water.
Further rises are not expected in the Warrego River but residents say they will not be able to relax until the water drops another metre.
Mayor Mark O'Brien says the river is likely to remain above seven metres until at least Monday night.
Meanwhile, searchers have recovered the body of a woman missing in floodwaters at Roma.
Her car was swept off a causeway into floodwaters on Friday.