Unseasonal heavy rain has caused rivers to overflow in the province of Buenos Aires.
Torrential rain has triggered flooding in northern Argentina and Uruguay.
About 2,000 people have already been evacuated in Argentina’s province of Entre Rios, according to Uruguayan newspaper El Pais.
Rainfall totals of more than 250mm have been reported in regions across both Uruguay and Argentina, causing the river levels to rise.
A number of families in Uruguay were preparing to be evacuated from their homes on Wednesday, after the Joint Technical Commission of Salto Grande announced that the Uruguay River was expected to rise to 12 metres at Puerto Salto.
Northern Argentina, Uruguay and southern Brazil often endure flooding during El Nino, when the waters of the Pacific Ocean are warmer than usual.
The current El Nino event has been one of the strongest on record, and the excessive amounts of rain has already triggered flooding in the region.
The torrential rain is expected to continue until Saturday, when the rain should slowly move away to the north.