"We did an assessment last week, 1,600 children are at immediate risk of dying from famine, thousands of others have malnutrition," he said.

On Friday, the United Nations' coordination body for humanitarian affairs OCHA estimated that 14,000 children in the region were malnourished.

Randindrarison said flooding caused by two cyclones that ripped through the Indian Ocean island in February and March had destroyed crops, causing food shortages.

"Normally the region is food insecure but flooding of crops this year made the situation worse," he said.

Madagascar is one of the world's poorest nations, with three quarters of its 17 million people living on less than a dollar a day. Aid agencies say the island's rates of child malnutrition are among the worst in Africa.