South America floods
Many rivers in South America have breached their banksJorge Adorno/Reuters

At least 150,000 people have fled the border areas of four South American countries after what the "worst flooding in 50 years", brought about by downpours caused by the El Nino weather pattern. Heavy rains have swollen three major rivers affecting Paraguay, Argentina, Uruguay and Brazil.

Paraguay is the hardest hit with around 130,000 people forced to evacuate their homes near the capital city of Asuncion, the BBC reported. About 7,000 residents of Alberdi, which lies south of Asuncion and close to the Paraguayan river, have also been asked to leave their homes.

President Horacio Cartes has declared a state of emergency in Asuncion and several nearby areas, and released $4m (£2.70m) to assist flood-hit families. According to reports, four people have been killed by fallen trees in Paraguay.

"(The flooding) was directly influenced by the El Nino phenomenon which has intensified the frequency and intensity of rains," Paraguay's national emergencies office said.

In Argentina's north-east areas, some 20,000 people have fled their homes. "We are going to have a few complicated months. The consequences will be serious," the governor of Argentine's Corrientes region, Ricardo Colombi, said.

At least two people have died in the floods in Argentina, where Entre Rios, Corrientes and Chaco provinces are the worst affected. National cabinet chief Marcos Pena said Argentina lacked proper infrastructure which will be addressed to prevent future flooding. He said government aid was on its way to flood-affected areas.

In Uruguay, some 9,000 people living near swollen rivers have been forced to leave their homes. The country's emergencies office said it expected the water levels in the rivers to remain high for several days.

In Brazil's south-eastern state of Rio Grande do Sul, at least 7,000 residents have left their homes, civil defence authorities told AFP.