Aid workers were struggling to help thousands of people affected by the floods which hit many areas of west and central Africa.
Severe food shortage
The country is also suffering from severe food shortages following a prolonged drought. The UN estimated that at least seven million people, more than half the population, are facing starvation in Niger.
Oxfam aid agency said on Tuesday that its aid operations were stretched to the limit as it tried to deal with "one of the worst food crises to hit the region in living memory."
"Many crops and vegetables that would have provided crucial food to hungry families have been destroyed by floods," Raphael Sindaye, Oxfam's deputy regional director in west Africa, said in a statement.
"People who were praying for rains for their crops to grow have now lost everything."
Ibrahim Mahaman, head of a flood-hit village told Oxfam "Before the rains, people lacked food, now any small reserves of grain they had have been washed away by the water. Nothing remains."
"Niger urgently needs more money to fund not only the food crisis but also to help those hit by this second emergency," Sindaye said.
Last week, the UN announced a further $15 million (12 million euros) for World Food Programme operations in Niger.
At least six people have died because of the heavy rains, which pushed the Niger river to its highest level for more than 80 years.