Deadly floods swept Australia's east coast Tuesday, stranding people on bridges and rooftops and forcing tens of thousands to flee their homes.

Dozens of emergency warnings are in effect across the states of Queensland and New South Wales, where a week-long "rain bomb" has dumped a metre (3.2 feet) of water on some areas.

Several waterways have burst their banks or broken through levees, inundating towns and forcing residents to evacuate or seek safety on higher ground.

Nine people have died and more than a thousand people have been rescued. Authorities have warned that more fatalities are likely.

The latest victim was a woman in her 80s whose body was found by police inside a home in the country town of Lismore.

"She is yet to be formally identified," said New South Wales Police.

In the usually laid back surf town of Byron Bay, Hannah Leser had enjoyed the weekend celebrating her wedding with 150 guests.

A Queensland Fire and Rescue crew move through the flooded streets of Paddington in suburban Brisbane
A Queensland Fire and Rescue crew move through the flooded streets of Paddington in suburban Brisbane AFP / Patrick HAMILTON

But the new bride and groom are now rescuing friends stranded in the nearby towns of Ballina and Mullumbimby in a borrowed four-wheel-drive.

About 30 people are camped at a house where the couple were to spend their honeymoon.

"It's chaos but all of our friends and family are safe," she told AFP. "This is not quite the honeymoon I expected but it is what it is."

Australia's military has deployed two MRH-90 Taipan helicopters to aid the rescue effort.

In one daring aerial rescue, the crew plucked two people to safety as muddy waters lapped at the corrugated metal roofing of their home.

Live television images on public broadcaster ABC showed a rescuer sitting on the roof with the pair, preparing to strap them to the chopper's winch.

"We've seen people stranded on roofs for hours, we've seen children being rescued, we're seeing people stranded on bridges," said New South Wales Premier Dominic Perrottet.

Flood warnings were in effect for dozens of areas across the states of Queensland and New South Wales, where a week-long "rain bomb" has dumped a metre of water
Flood warnings were in effect for dozens of areas across the states of Queensland and New South Wales, where a week-long "rain bomb" has dumped a metre of water QUEENSLAND FIRE AND EMERGENCY SERVICES via AFP / Handout

Emergency services were overwhelmed by calls for help and flotillas of makeshift rescue boats fanned out across towns as people tried to ferry their neighbours to safety.

In Lismore, local member of parliament Janelle Saffin had to swim to safety after she was stranded in the floodwaters.

"We went to the verandah, hanging on to the rafters," she told Nine Newspapers.

Local resident Danika Hardiman was rescued Monday after she woke up to find floodwaters had reached the balcony of her second-floor apartment in the town's main street.

She and her partner managed to climb up to the roof and were eventually rescued by "two guys in a boat, two locals", she told AFP, describing the scenes in Lismore as "horrific".

"Imagine you're in a boat sailing past people's roofs," she said.

Makeshift evacuation centres have been set up in primary schools, recreation centres and retired service members' clubs.

Travis Lavdaras headed for Ballina Airport, where the departure lounge was filled with families, holidaymakers and the elderly trying to escape.

"There were big lakes' worth of water on either side of the highway" on the way to the terminal, he said, with many flights cancelled and an evacuation ordered for the area nearby.

Near the town of Grafton, the scale of the disaster was thrown into stark relief by the sight of buildings submerged almost to roof level, roads washed away and cattle roaming abandoned.

Australia has been on the sharp end of climate change, with droughts, deadly bushfires, bleaching events on the Great Barrier Reef and floods becoming more common and intense as global climate patterns change.