At least 143 people have now died in the floods in Brazil

The death toll from heavy rains in the Brazilian state of Rio Grande do Sul rose to 143 from 136 the previous day, according to the local civil protection agency, while another 125 people remain missing.

On Saturday evening, the government announced emergency spending of around 12.1 billion reais (AU$3.54 billion) to address the crisis, which has displaced more than 537,000 people in the state out of a population of around 10.9 million.

With this new money, more than 60 billion reais (A$17.54 billion) in federal funding has already been made available to the state, the federal government said in a statement on Saturday.

More rain is expected on Sunday, filling already overflowing or overflowing rivers, weather forecaster Metsul said Saturday evening.

The state lies at a geographical intersection between tropical and polar atmospheres, which has resulted in a weather pattern with periods of intense rainfall or drought.

Local scientists believe the pattern has intensified due to climate change.