The U.N. Office for the Coordination of Humanitarian Affairs estimates that more than 15 million people are facing food shortages and malnutrition due to a lingering drought.
OCHA Director of Operations John Ging said after returning from the region that more than 200,000 children died of malnutrition last year and more than 1 million children are threatened.
"We are in a race against time and some of the harshest climatic conditions on the planet," he said. "This is already an appalling crisis in terms of the scale and degree of human suffering and it will get worse unless the response plans are properly funded."
The food and malnutrition crisis is compounded by what the U.N. Security Crisis described as a deteriorating humanitarian crisis.
Around 100,000 refugees have fled Mali to neighboring countries following rebel fighting and a later military-led cup.
"It's a matter of life or death for millions who are on the brink," said Ging.