Ban addressed members of the Luxembourg Parliament on the series of cascading crises gripping the Sahel region.
"The statistics are sobering: 15 million people are directly affected," Ban said. "More than 200,000 children died of malnutrition last year and another 1 million are threatened right now."
The U.N. Office for the Coordination of Humanitarian Affairs said a food and nutrition crisis in the region is deteriorating rapidly.
Meanwhile, the aftermath of the 2011 civil war in Libya created security complications in the region as armed fighters and criminal gangs returned home with large quantities of weapons, the secretary-general warned.
The Tuareg rebellion in northern Mali was fueled by militants who had fought alongside fighters loyal to Libyan leader Moammar Gadhafi.
"Simply put, we must do more and do it quickly," said Ban. "Across the region, we see growing conflict and unrest, more people being displaced, rising food and fuel prices and severe drought."
The International Committee of the Red Cross said the situation in northern Mali was approaching the critical stage.