Men selling vegetables drive their horse-drawn cart through a flooded street in the Tacumbu neighborhood of Asuncion, Paraguay, Wednesday, Dec. 23, 2015.
Paraguay was the worst hit of the three countries, with around 100,000 people evacuated up to Wednesday after the Paraguay River burst its banks.
Two minors died and close to 20,000 people were evacuated Friday in northeastern Argentina due to the flooding of the rain-swollen Uruguay, Parana and Paraguay Rivers.
Three people traveling Paraguay's worldwide Route 2, which links Asuncion and Foz de Iguazu in Brazil, were killed when a tree fell on their vehicle before dawn.
Emergency personnel were carrying out rescue and evacuation operations, said David Arellano, the head of operations for the National Emergency Secretariat (SEN).
A 13-year-old boy was electrocuted by a power cable while trying to assess storm damage to his home in the city of Corrientes, local media reported.
Entre Rios province was the worst off with about 10,000 people displaced, a lot of them in Concordia, a city of some 170,000 located on the banks of the river where officials said it was the most serious flooding in 50 years.
More than 9,000 people in Uruguay also had to flee their homes, according to the national Emergency Office, which added that it expected water levels to remain at their current level for several days before subsiding.
As the river level has risen, so too has the number of refugees, and the watercourse now stands at its highest level in the last 20 years.
Flooding sparked by days of torrential rain in Paraguay, Uruguay and Argentina led officials to evacuate tens of thousands to shelters.
And it could affect thousands of other people who live by the Paraguay - the country's main river - the authorities said. "While there are floods in the southern cones, drought has been affecting parts of Colombia, and reservoirs are running dry there".