In a dramatic symbol of the disaster, rescuers saved a horse that had been trapped precariously for two days on a rooftop in a badly flooded town.
More rains are forecast in the coming days, raising fears that water levels will rise further in the inundated state capital of Porto Alegre and nearby town where streets have turned into rivers.
At least 136 people are still missing and more than 165,000 have been displaced from flooded homes and rescued by boats and helicopters.
Television images showed the horse straddling the roof of a farmhouse on the outskirts of Canoas, a town north of Porto Alegre. The animal was secured by firemen and loaded into a Zodiac inflatable boat to take it to safety.
A horse was found stranded on a rooftop in a flooded area in Brazil's Rio Grande do Sul.— ABC News (@ABC) At least 100 people have died in recent days as floods have struck the region.Read more: https://t.co/RUFbJDhcdX pic.twitter.com/TskQT3YzwwMay 9, 2024
The floods have destroyed infrastructure and bridges, blocking access to Porto Alegre, where supermarket shelves are empty and looting has been reported at night.
Governor Eduardo Leite said initial calculations indicate that Rio Grande do Sul will need at least 19 billion reais ($A5.56 billion) to rebuild from the damage, which has extended into farm areas around the capital.
"The effect of the floods and the extent of the tragedy are devastating," he said on social media.
In Brasilia, the federal government estimated the fiscal impact of the flooding at 7.7 billion reais, mostly due to the injection of funds into a support program for small businesses hit by the floods.
"This doesn't end here," President Luiz Inacio Lula da Silva said at an event announcing steps to help the stricken state.
Lula said the full extent of Rio Grande do Sul's needs would be known only when the water recedes.
