Surging floodwaters broke levees in disaster-hit Australia on Monday to inundate more properties in the southeast, as residents sandbagged homes against the spiralling crisis.

Swollen rivers in the southeastern state of Victoria have created a flood zone measuring an estimated 90 kilometres (56 miles) long and 40 kilometres wide, the State Emergency Service said.

"This area has seen unprecedented flooding," SES spokesman Kevin Monk told AFP. "This is just amazing."

As the floodwaters rushed towards the Murray River, evacuation alerts were issued late Sunday and early Monday for the small communities of Pental Island and Murrabit West, home to about 400 people each.

In an emergency alert the SES said that levees around Murrabit West were failing, warning that the area would be inundated in the next 12 hours.

"They are being flooded now," Monk told AFP. "It's across properties. If they haven't sandbagged them, there may be some impacts on people's housing."

The Victoria floods stem from La Nina-provoked torrential rains which hit the state mid-January and followed weeks of widespread floods to the north that killed at least 30 people and devastated mining and farming in Queensland.

Prime Minister Julia Gillard again called on companies to boost their donations to the rebuilding effort, with infrastructure repairs and help for businesses and families estimated to cost some Aus$20 billion ($19.8 billion).

Champion American cyclist Lance Armstrong, who has been in Australia for the Tour Down Under in Adelaide, did his part, leading some 2,500 people on a Queensland Ride Relief fundraiser around Brisbane.

The seven-time Tour de France winner praised Queenslanders for the way they had rallied after the disaster, saying he had heard that so many people had driven into Brisbane to help clean up they caused traffic jams.

"You know what that is? That's a whole lot of heroes the whole world needs to pay attention to and copy that," he said.

"I can tell you, having lived in the United States and having watched (Hurricane) Katrina closely, there were no traffic jams going into New Orleans. So for you guys to step up like that, is unbelievable."

As Queensland begins the massive recovery phase, Victoria is dealing with a record-breaking deluge which has so far affected more than 1,700 properties in the rural northwest of the state.

Emergency officials have been preparing for potential flooding along the Murray River -- a vital lifeline in the southeast which had been hard hit by a recent protracted drought -- since record rainfalls in mid-January.

The regional centre of Swan Hill, with a population of about 10,000, was bracing for floodwaters to peak on Thursday or Friday with residents frantically sandbagging but officials expecting the levee to hold.

earlier related report
2010 'one of worst' years for disasters: UN
Geneva (AFP) Jan 24, 2011 - 2010 was one of the worst years on record for natural disasters over the past two decades, leaving nearly 297,000 people dead, research for the United Nations showed on Monday.

The devastating earthquake in Haiti a year ago accounted for about two thirds of the toll, killing more than 222,500 people, according to the Belgium-based Centre for Research on the Epidemiology of Disasters (CRED).

The CRED found that the summer heatwave in Russia was the second deadliest disaster of the year, leaving 55,736 people dead according to figures it compiled from insurers and media reports of official sources.

The year was "one of the worst in decades in terms of the number of people killed and in terms of economic losses," Margareta Wahlstroem, UN special representative for disaster risk reduction, told journalists.

"These figures are bad, but could be seen as benign in years to come," she said, pointing to the impact of unplanned growth of urban areas, environmental degradation and climate change.

The economic cost of the 373 major disasters recorded in 2010 reached 109 billion dollars, headed by an estimated 30 billion dollars in damage caused by the powerful earthquake that struck Chile in February.

The earthquake unleashed a tsunami that swept away villages and claimed most of the 521 dead.

Summer floods and landslides in China caused an estimated 18 billion dollars in damage, while floods in Pakistan cost 9.5 billion dollars, according to the CRED's annual study.

Although impoverished Haiti is still struggling to recover from the quake that devastated much of the capital, Port-au-Prince, it ranked lower down the global economic scale with an estimated eight billion dollars in losses.

Asians accounted for 89 percent of the 207 million people affected by disasters worldwide last year, the CRED said.