Food shortages are reported in the northern town of Trizidela do Vale
The Brazilian authorities say almost 408,000 people still cannot return home because of floods that began last month in the north of the country.
The bad weather is forecast to persist for another fortnight.
The government has released more than $435m (£273m) in aid for victims of the flooding in the north and north-east of Brazil.
A BBC correspondent says the damage across the region runs into hundreds of millions of dollars.
Forty-nine people are said to have died across 12 states and many small farmers say the flooding has devastated this year's crops, the BBC's Gary Duffy reports from Sao Paulo.
Nearly 400,000 children are also missing classes either because roads are blocked, classrooms are under water, or schools are being used as shelters to accommodate the homeless, he adds.
The situation is said to be most critical in the state of Amazonas, where a quarter of all pupils are affected.
Despite the government's emergency aid, there are reports from the worst-affected areas that help is not reaching those who need it most.
In the northern town of Trizidela do Vale, food supplies are said to be insufficient to meet demand, despite pleas from local community leaders, our correspondent says.
Experts say global warming may be behind the wild climate swings that have brought periods of unprecedented droughts and flooding to the Amazon in recent years.
Aerial footage of floods in north-east Brazil in early May