The devastation caused by the cyclonic weather will continue for days, with thousands of homes inundated, entire communities isolated and the possibility that Brisbane could run out of drinking water.
Four people have died in the disaster, all in Queensland. A three-year-old boy hit by a falling gum tree while watching floodwaters in Brisbane is the latest victim.
His 34-year-old pregnant mother remained in a critical condition in hospital on Tuesday night with several broken bones and severe head injuries.
Meanwhile, 130 patients at Bundaberg Hospital had to be flown to Brisbane by the Australian Defence Force, as the city suffered its worst flood.
Four military helicopters and several civilian ones also performed more than 1000 air rescues, lifting stranded residents off roofs in North Bundaberg.
While the rain eased, the immediate danger did not subside.