Brazil flood death toll rises to 137

The death toll from storms in southern Brazil that have caused unprecedented floods has risen to 137, according to the latest report by the Civil Defence.

At least 141 people are still missing, while more than 400,000 have been displaced.

In total, 444 cities have been affected and 1,950,000 people have been affected by the storms in the region.

The most serious situation is in Rio Grande do Sul, a state bordering Argentina and Uruguay, where at least 136 people have died and 756 have been injured.

The other death was reported in the neighbouring state of Santa Catarina, which has also been affected by the disaster, although to a lesser extent.

After the rains had eased somewhat in the past few days, the heavy downpours resumed on Saturday, especially in the Taquari Valley and in Porto Alegre, the capital of Rio Grande do Sul.

The storms that have hit the region in the past two weeks have left a trail of chaos and destruction leaving dozens of cities such as Porto Alegre have been totally or partially submerged.

Hundreds of roads have been destroyed or blocked, while flood victims are suffering from limited public services, including hospitals.

The situation has also hindered the work of some 28,000 workers - including firefighters, security forces and volunteers - who are helping in rescue efforts and distributing humanitarian aid.

In the last few hours, more cities have flooded after the Lagoa dos Patos lagoon overflowed.

The situation could worsen in the coming hours, as strong winds and a drastic drop in temperature are forecast in addition to the heavy rains.

Rio Grande do Sul, an important agricultural centre, will need at least 18.839 billion reais ($A5.5 billion) to recover from the floods, according to regional government estimates.

Brazilian President Luiz Inacio Lula da Silva has announced a 50 billion reais aid package for the state, which includes direct assistance measures, subsidised credits for companies and aid for rural producers, among others.