Nova Friburgo: Brazilian officials began on Wednesday moving thousands of people out of at-risk areas near Rio in a flooding disaster that has already left at least 739 people dead.

Ten teams of civil defense and environment officials were evacuating residents in outlying areas of Nova Friburgo, the hardest-hit town, said their commander, Colonel Roberto Robadey.

"We are telling people in the risky houses they have to go," he told AFP.

Robadey said 6,000 people were living in at-risk areas before the disaster, adding that definitive figures were not available.

Reactions from inhabitants ranged from surprise to regret at being ordered to evacuate places that many of them have lived in their whole lives, but most signed documents accepting the move. The terror of what they experienced over the past week was evident.

"So far, people are cooperating, accepting it, because they are panicked after what happened. But if any resist, we will have to mount a tough operation to get them out," Robadey said.

The disaster that hit the Serrano mountain region on January 12 was considered the deadliest natural catastrophe on record in Brazil, according to media.

Seasonal rains, normally heavy anyway, suddenly intensified unimaginably because of a cold front that dumped a month's worth of water in a few hours.

Houses illegally built on the hillsides - many of them by poor people occupying public land - were immediately destroyed, and added to the deadly mass speeding downhill. Wealthy properties were also submerged.

Towns and villages hit by the flooding and mudslides are awaiting millions of dollars in government aid as civilian and military personnel fan out to cut-off communities, providing rescue and supplies.

Faced with the first big challenge of her mandate started January 1, President Dilma Rousseff has released $60 million of immediate aid.

The World Bank said on Tuesday it would lend Brazil another $485 million for rebuilding and disaster prevention efforts, with the first tranche of $290 million expected to be approved within weeks.

Rio de Janeiro's state health and civil defense service gave the death toll on Wednesday as 739.

It said 353 people died in Nova Friburgo, 302 in Teresopolis, 63 in Petropolis and 21 in the village of Sumidouro.

Around 14,000 people were being put up in shelters or staying with relatives after losing their homes or having to abandon at-risk areas.

The fatality count of the catastrophe far overshadowed contemporaneous floods in Australia, where more than 30 people have died; Sri Lanka, where at least 43 died; and the Philippines, which saw 53 victims.

In the wake of the mudslides, Brazil is accelerating a long-delayed project for a computerized disaster warning system amid criticism that the extent of the tragedy could have been minimized.

"The rain last week in Rio was forecast. Alerts were sent. But when the alerts arrived, the municipalities didn't have the structures to react," said Jose Eloi Guimaraes of the Geosciences Institute at the University of Brasilia.

The plan notably called for a network of 400 rain-measuring monitors and sirens in 61 communities in the Serrana region, as well as ensuring that emergency personnel had cellphones to pass on warnings.

The science and technology ministry, involved in the project, said the complex system would be partially functioning at the end of this year and fully operational in 2014.

According to the ministry, five million people in Brazil live in 500 identified areas at risk of a natural catastrophe.