Storms and floods battering South America claimed a sixth victim in Paraguay on Monday as river levels threatened to rise further after torrents drove tens of thousands from their homes.

The death of a technician who was electrocuted while trying to restore power to a Paraguayan village brought the toll across three countries to at least 12 overall.

Over recent days the storms blamed on the "El Nino" weather phenomenon have killed four people in Brazil and two in Argentina. Officials say rainfall has driven at least 160,000 people from their homes in Paraguay, Argentina and Uruguay.

The director of Paraguay's weather service, Julian Baez, told reporters the level of the Paraguay River had risen to nearly eight meters.

If rains continue as forecasters expect, the flood levels could tie or pass their record of nine meters in 1983, when the capital's busy port area was under water, Baez warned.

The National Emergency Secretariat warned that a dike near the village of Alberdi risked giving way if the Paraguay River kept rising.

The waterway, which forms a border between Paraguay and Argentina, rose by an additional two centimeters on Monday.

"It is a situation of nature that we have to live with," said Paraguayan President Horacio Cartes, while visiting Alberdi on Monday.

Elsewhere, driving rains in the Sao Paulo area in southern Brazil triggered a mudslide that killed four people, state officials said on Sunday.

In Uruguay, between Argentina and Brazil on the South Atlantic, more than 16,300 people have fled their homes because of the floods, the National Emergency System said on Monday.

In northeastern Argentina, two people were killed and about 20,000 were evacuated from their homes by the flooding of the Uruguay River.

"The situation has stabilized. There are still 20,000 people evacuated," Argentine Interior Minister Rogelio Frigerio told a news conference.

Most of those were in the eastern city of Concordia.

"If it starts raining again like it did last week, we are going to have difficulties," said Gustavo Bordet, the governor of the surrounding province of Entre Rios.

International environmental group Greenpeace said in a statement that the flooding devastation was due to a combination of increased rain and deforestation, which destroys woodland that otherwise absorbs rainwater.

El Nino is associated with a sustained period of warming in the central and eastern tropical Pacific.

Last month, the UN's World Meteorological Organization warned the current El Nino was the worst in more than 15 years, and one of the strongest since 1950.