A Brazilian Navy ship has arrived in the coastal city of Sao Sebastiao to help rescue victims of heavy rains that have killed at least 50 people and displaced thousands in southeast Brazil.

The Navy's multipurpose aircraft ship, its largest vessel, will serve as an emergency field hospital and is equipped with helicopters and landing vehicles as well as hospital beds.

Last weekend's rainfall - the heaviest ever recorded in Brazil in a 24-hour period, according to government data - left a trail of destruction along the coast of northern Sao Paulo state.

At least 38 people remain missing, while more than 3000 have been forced to flee their homes, according to a statement from Sao Paulo's state government.

Sao Sebastiao, located some 200km from the metropolis of Sao Paulo, bore the brunt of the storms including almost all of the reported deaths, as massive downpours provoked landslides and dangerous flooding.

More rainfall is expected in the coming days as humidity from the Atlantic Ocean and the Amazon rainforest creates conditions for "moderate to heavy showers", according to the state government.