SYDNEY - Two weeks ago, the town of Forbes in south-east Australia experienced one of the worst flooding disasters in decades after a river broke its banks, sending water rushing into homes and cutting off roads and highways.

The town’s residents had only just begun to recover when further rains caused a return of the flooding this week.

About 1,000 of the town’s 9,000 residents have been evacuated, and the town has been split in two. Hundreds of homes and businesses are underwater, including many that had previously been submerged in the earlier flood. Schools have been closed, and motorboats now ferry people and goods across town above roads that have turned into waterways.

“We’ve got people who have lost absolutely everything here,” Forbes Mayor Phyllis Miller told AAP.

Across south-east Australia, residents have spent more than two months in the grip of devastating floods that are causing mass evacuations, destroying houses and farmland, and bringing life to a standstill.

In the state of New South Wales (NSW), more than 110 flood warnings and 23 evacuation orders were in place on Thursday.

The state’s authorities are being assisted by 200 Australian Defence Force troops, and a team of 18 Singaporean flood rescue specialists, as well as a 24-person team from New Zealand. A team from the United States will arrive soon. The support will help to relieve exhausted Australian emergency services teams, who have dealt with more than 65 days of consecutive heavy flooding.

NSW’s Minister for Flood Recovery Steph Cooke said on Thursday that she was “deeply grateful” for the international support, saying the state’s emergency services agency had never previously reached out for overseas help.

“The flooding we are currently seeing, on top of disastrous flooding already this year, is stretching our emergency services to the very limit,” she said in a statement.

“This unprecedented flooding requires an unprecedented response and thankfully, our emergency services friends from overseas are answering the call for help.”

Several people have been killed in the floods, including a 60-year-old woman whose car was swept away by flood waters in the small town of Eugowra.

Eugowra resident Lyn Ellis on Thursday described her and her husband Hugh’s rush to escape to the roof of their house as a “wave” of water came rolling through the usually quiet inland town.

“The whole building was shuddering and shaking,” she told ABC News.

“I thought, ‘This is it. There’s no way out of here’. And at the eleventh hour, Hugh finally broke through with the wood, and we got up on the roof and the helicopters were there.”

The floods have followed heavy rain that has come during an unusual period of three consecutive years of La Nina events. In the past 19 months, eastern Australia has experienced five major floods. And the long stints of rain have left rivers and dams full and have saturated soils, so that any further downpours can cause immediate and serious flooding.

The NSW government said it will be the largest flood operation in the state’s history.

NSW Premier Dominic Perrottet told reporters this week: “It’s not taking much rain to cause flash flooding anywhere across our state.”

The federal government said the cost will far exceed the A$3 billion (S$2.75 billion) that has been allocated to assist with recovery and support. The floods have ruined crops, killed livestock, and damaged roads and equipment that are crucial for the farming sector.

Federal Emergency Management Minister Murray Watt, told reporters: “The overall cost of the current flood disaster, I can guarantee you, is going to be in the billions.

“With each week these floods go on and with each road damaged, the damage bill is going to go up.”

Unfortunately, there is not expected to be any immediate end to the deluge.

The Bureau of Meteorology said on Thursday that river levels around Forbes will remain high until the weekend.

“Residents and communities living on or near any rivers, creeks and streams, or in low-lying areas, should stay up to date with the latest forecasts and warnings,” the bureau said in a statement.