Dozens of people were evacuated from homes and cars and many roads closed because of rising flood waters and fallen trees after the Sunshine Coast was lashed with days of torrential rain, officials said.

Emergency Management Queensland regional director Peter Twomey said the floods were now receding and the damage was believed to be minimal because of the use of thousands of sandbags to hold back the water.

"Major flooding has affected residents in the Noosa River, Lake Cooroibah and Lake Cootharaba area and even though we are confident the worst is now past us, it may take several days for waters to return to normal levels," he said.

The dumping of more than 1,000 millimetres (40 inches) of rain on the Sunshine Coast has been attributed to a once-in-a-century weather event.

Bureau of Meteorology senior forecaster Jeff Callaghan said the low pressure system over southeast Queensland that caused the downpour was a freak event not seen at this time of year since the 1800s.

"They are very rare in August and the last one we can find was probably in the 1880s," Callaghan told the Australian Broadcasting Corporation.

"We know they happen now but we haven't in the past had any of these events in August or September."

The bureau said while the major risk had passed, areas along the Noosa River would remain flooded until Monday.