BEENLEIGH (Australia) • A woman's body was found and tens of thousands of people were evacuated from towns in two Australian states yesterday after torrential rain caused by a powerful tropical cyclone lashed the region.

Category four Cyclone Debbie hit north-eastern Australia on Tuesday between Bowen and Airlie Beach in Queensland state, ripping up trees, washing boats up on land and causing widespread damage, reported Agence France-Presse (AFP).

Debbie was downgraded to a tropical low as it tracked south-east but continued to pack damaging gusts and dump huge amounts of rain.

The devastation stretched 1,000km from Queensland state's tropical resort islands and Gold Coast tourist strip to the farmlands of New South Wales state, with more than 100,000 homes reportedly without power, reported Reuters.

Five regions - Tweed, Lismore, Byron, Richmond Valley and Ballina - were declared natural disaster zones by the government.

It means that Commonwealth Funding would be made available for local councils to restore, clean and repair public assets, reported Xinhua.

NSW Police said the body of a woman who "disappeared in floodwaters overnight from a rural property" near Murwillumbah, just south of the Queensland border, was found yesterday, reported AFP.

Six large rivers had hit major flood levels and were still rising, said the Bureau of Meteorology.

Flood sirens sounded before dawn at Lismore when the Wilsons River surged over the town's levee.

By daybreak, the centre of the town of 25,000 people in the Northern Rivers region of NSW was underwater, reported Reuters.

NSW State Emergency Service acting deputy commissioner Mark Morrow said yesterday he had fears for some missing residents from Lismore. "As we start to go out and try to find people that made... calls overnight, there could be some very distressing news," he told the Australian Broadcasting Corporation.

"There could be people overnight that perished in that flood, we don't know at this stage."

Since Wednesday night, the NSW State Emergency Service has fielded 1,400 calls and made 300 flood rescues. It has also given more than 20,000 people immediate evacuation orders.

Other towns subject to evacuation orders included Tweed Heads, Condong and Tumbulgum, reported The Sydney Morning Herald.

Further north in Queensland, the popular tourist city of the Gold Coast and nearby regions were also inundated by water, with the authorities warning that Brisbane - the country's third-largest city - may face flooding, reported The Telegraph.

Queensland Premier Annastacia Palaszczuk said some 2,000 properties had been assessed, with about 270 severely damaged, reported AFP.

"The army is doing everything it can to get water into those parts of North Queensland that I mentioned - Airlie, Proserpine, Bowen and the Whitsunday islands," she told reporters. "We also have structural engineers who are on the ground at the moment."

Upper Springbrook in the Gold Coast hinterland recorded 789mm of water on Thursday, the Bureau of Meteorology said.

The military has mobilised 1,300 soldiers to help assess the full extent of damage and aid the clean-up, with helicopters and planes deployed to restore infrastructure and supply food, water and fuel.

Stranded residents climbed onto roofs of flooded homes to await rescue but fast-moving water and high winds hindered emergency crews reaching some people.

Farmers moved livestock to higher ground.

Others sandbagged property to stop floodwaters.

The Insurance Council of Australia declared the Queensland and northern NSW regions disaster zones, adding that the damage bill could reach A$1 billion (S$1.1 billion), reported AFP.

"There's not a lot we can do about it, you can't change mother nature's mind, you just do your thing, wait till it goes down and clean it up," Mr Lennon Bartlett told Reuters as he paddled his dad's rowboat down a street in Lismore.