More than 10,000 Australians were Friday stranded by flooding in the country's east, with thousands ordered to leave their homes or businesses and the military called in to airlift supplies.

The New South Wales State Emergency Service said about 10,500 people were thought to be isolated by the waters that have rushed across the state's north and southeast Queensland after days of constant rain.

More than 2,000 people have been ordered to evacuate buildings in the New South Wales town of Moree, which is preparing for its second flood in a matter of months.

"This one's going to be worse," Moree mayor Katrina Humphries told national broadcaster ABC.

"People who got a bit of water last time know to be prepared to get a lot more water this time."

A Royal Australian Air Force C-130 Hercules aircraft is moving humanitarian supplies to Moree, as locals sandbagged buildings against the rising Mehi and Gwydir rivers, which are expected to hit levels not seen in close to 40 years.

"It's a huge logistical operation with a major flood," SES Deputy Commissioner Steve Pearce told the Seven Network.

"There have been some circumstances where we've had to use one if not all of our 18 helicopters to airlift people out of some isolated areas.

"Fortunately most people abided by those evacuation orders."

Further north in Queensland state, some 15 homes have reportedly been flooded after the Maranoa river swelled overnight while scores of people spent the night in evacuation centres.

The floods come just over a year after massive floods deluged much of Queensland and northern New South Wales, swamping mines and farmland, wiping out entire hamlets and bringing the city of Brisbane to a watery standstill.

Humphries said while Moree was well prepared, there was no telling when the downpour would end.

"Mother Nature has her way and she'll stop crying when it suits her," she said.