Residents of the regional Queensland town of Warwick are anxiously watching the rising Condamine River, with 30 homes already flooded and more expected to go under.
The swollen Condamine has cut Warwick in two and about 180 people have gathered in two evacuation centres, Southern Downs Mayor Peter Blundell says.
The river is expected to peak at eight metres at about 8pm (AEST) on Monday, about the same level as December 2010.
If the peak is reached, 92 houses and 17 businesses will be affected by water.
The only road into town that hasn't flooded is the New England Highway to the south.
Mr Blundell says an influx of people trying to get home from the Tamworth Music Festival are stuck in the town and sheltering in their caravans on the side of the road.
"We do have a lot of water in catchments that's been there for a long time, longer than we've seen previously, so it will be slightly new ground to work out how long this one takes to subside," he told AAP.
Upstream at Dalby, houses have so far escaped floodwaters but Western Downs Mayor Ray Brown says if the Myall Creek reaches the expected peak of three metres that will change.
He said the level is well short of the 3.74m level reached in 2010-2011 but residents are still on edge.
"You tell that someone that got flooded that it's less water (than before); they don't care. When you're wet you're wet," Mr Brown told AAP.
Eight businesses in Chinchilla, northwest of Dalby, have been inundated and three families in the town have fled their homes.
Mr Brown said five families had evacuated homes around the rural township of Moonie, southwest of Dalby.
The township of Tara, population 1200, has been isolated.
Meanwhile, the town of Condamine, west of Chinchilla, is facing a significant flood event with a peak of 12 metres expected on Thursday or Friday.