Heavy rain has been falling in eastern Australia, bringing fresh misery to flood-hit communities where hundreds of homes are already under water.
Forecasters predict central and southern Queensland will be worst hit by the latest deluge, which will last into the weekend.
In Rockhampton, however, waters are slowly starting to recede after the Fitzroy river peaked on Wednesday.
The town of St George is braced for the Balonne river to peak by Sunday.
About 1,200 homes across Queensland have been inundated since heavy rains set in last month, with another 10,700 suffering some damage, officials say.
Four thousand people have been forced from their homes.
Meteorologist Bryan Rolstone, quoted by Australian broadcaster ABC, said the latest rain would fall in the Wide Bay-Burnett region, affecting Rockhampton and the city of Bundaberg, which has also already suffered severe flooding.
State disaster co-ordinator Ian Stewart described the forecast as "worrying".
"We're watching the rain patterns very, very carefully," he said.
In Rockhampton the Fitzroy river was said to be receding very slowly, after hitting a peak of 9.2m (30ft) on Wednesday.
But officials said they expected water levels to remain over 8.5m - the major flood level - for several more days.
Local Mayor Brad Carter said that clean-up operations in the town of 75,000 people could take up to a year.
Further south in St George, residents have filled about 10,000 sandbags and more were being prepared in an attempt to protect homes.
But it now appears that water levels in the Balonne River will not rise as high as predicted.
"The information we had originally was 14m on Saturday and possibly could creep just above that [on] Monday [or] Tuesday," ABC quoted Mayor Donna Stewart as saying.
"The information that we've just had is that we'll reduce that and that it will be under that 14m."
Some residents have begun returning to Theodore, one of the first places to be swamped by the floods.
But heavy rain delayed the return of the 150 residents of Condamine in south-west Queensland, who were airlifted to safety a week ago when the local river flooded.
The town has no electricity or running water, and the schools and churches are also flooded.
Even in parts of Queensland which are beginning to dry out, an influx of snakes is making it dangerous for people to return to their flooded homes.
"There is a lot of snakes - and I mean a lot," Rockhampton resident Shane Muirhead told ABC. "Like every hundred yards you will see a snake. They are just everywhere."
Saltwater crocodiles are posing another hazard.
Rockhampton Mayor Brad Carter hit out at residents who refused to leave flooded homes, saying they put those who were getting supplies to them through snake-infested waters in danger.
"We have taken a decision, and we make it very clear, that we cannot put emergency services resources at risk bringing in those supplies," he said.
With natural disasters declared across an area of a million square kilometres, Queensland Premier Anna Bligh said the flooding was unprecedented in her state and had now directly affected 40 communities.
She said floods that have closed dozens of mines, railways and ports would send coal and steel prices soaring.
Queensland produces about half the world's coking coal used to make steel.
"Seventy-five percent of our mines are currently not operating because of this flood, so that's a massive impact on the international markets and the international manufacture of steel," she told the Seven network TV station.
Prime Minister Julia Gillard has appointed a cabinet minister, Joe Ludwig, to lead the reconstruction effort.