Women walk through flood waters in Rockhampton. (Daniel Munoz/Reuters)

Floodwaters from a swollen river poured into businesses and homes in another northeastern Australian community as relentless rain means more misery to a region battling its worst flooding in decades.

Muddy waters flowed through the main street in the city of Gympie, the latest of roughly 40 communities in Queensland state to be drenched by overflowing rivers in recent weeks. Gympie residents were frantically sandbagging buildings, but about a dozen businesses were inundated by Monday morning and dozens more were at risk as the Mary River burst its banks and kept rising.

The latest flooding was not as bad as in recent weeks when entire towns were submerged beneath an inland sea the size of France and Germany combined. But it was a sign that the ground has little capacity to absorb any more moisture, so any new rain is likely to make matters worse, officials said.

Some areas of Queensland have had more than 343 millimetres of rain in the past 24 hours, the Bureau of Meteorology said Monday.

Up to 80 businesses and homes were at risk of being inundated in Gympie, a city of 16,000, said acting Regional Mayor Tony Perrett.

Police were planning to knock on doors in high-risk areas to warn residents they might need to flee, Perrett said.

"If it looks like [it's] getting to be a life-threatening situation somewhere, we'll certainly get people out," he told Australian Broadcasting Corp.

The water was already 1.5 metres deep at Gympie's Royal Hotel on Monday morning.

"You want to cry," hotel assistant manager Jess Philpot said. "It's going to go up to the roof."

Ten people have died since late November and about 200,000 have been affected by the floods. Roads and rail lines have been cut, Queensland's big-exporting coal mining industry has virtually shut down, and cattle ranching and farming across a large part of the state are at a standstill.

Residents of some of the affected communities have returned home and begun mopping up sludge left behind by the floods, while others — including in the city of Rockhampton, home to 75,000 people — are still waiting for floodwaters to recede to start the cleanup.

Water levels remained stubbornly high in Rockhampton on Monday, and the mayor warned weary residents ordered out two weeks ago that they face another week of waiting before it will be safe for them to return home. Muddy water is still sloshing through 400 houses and 150 businesses in the city.

Officials were putting together cleanup kits for residents, complete with brushes and cleaning agents. But the process of clearing out the damage was expected to take a long time, and conditions were far from optimal.

Mosquitoes, black flies and other pests breeding in the stagnant, mucky water were only going to increase, Rockhampton Mayor Brad Carter said, with rotting vegetation leaving a putrid smell throughout the city.

"The stench will be quite uncomfortable for some time in this town," he warned.

Queensland officials have said the price of rebuilding homes, businesses and infrastructure, coupled with economic losses, could be as high as $5 billion.

Australia's worst flooding in some 50 years was caused by tropical rains that fell for days, starting just before Christmas. Some 1,200 homes were inundated and almost 11,000 more have water damage. Nearly 4,000 people were forced from their homes and many are still staying with friends or in relief shelters.