Nearly 500 people were evacuated in Curitiba, the state's capital that also serves as the base camp for defending cup champions Spain, who arrived on Sunday.
Nigeria and Iran will play in Curitiba's 43,000-capacity Baixada Arena on June 16 followed by Spain-Australia on June 23.
Authorities had reported nine deaths over the weekend. Most of the victims are in the interior of the state.
The flooding has affected the homes of half a million people to various degrees, civil defence officials said.