The World Bank has announced more than $500 million in aid to help victims of the worst drought in East Africa in 60 years, as the UN held an emergency summit in Rome to discuss the crisis.

The World Bank also announced an extra $12 million in "immediate aid" for those 11 million people in the region who have been affected.

"Immediate relief and recovery is the first priority, and it is important to act fast to reduce human suffering," said World Bank President Robert B. Zoellick. "But we also have an eye on the long term solutions of economic recovery and drought resilience that are key to re-establishing livelihoods and ensuring that droughts don't take such a heavy human toll in the future." 

The new funding will support efforts to restore livelihood in the region and scale up local drought resilience projects, and has been found by restructuring existing programs and fast-tracking new ones.

The $12 million that will be immediately available will be used to help find and deliver aid, and also to ensure that farmers will be able to plant seeds in time for the next harvest.

The announcement was made as the head of the UN's food programme, Josette Sheeran. said the drought was "the worst I have ever seen" outside an emergency meeting in Rome.

"What we saw is children who are arriving so weak that many of them are in stage four malnutrition and have little chance, less than 40 per cent chance, of making it," Sheeran told reporters.

"These children are extremely weak. It is the worst I have ever seen."

The one-day session in Rome was held at the headquarters of the Food and Agriculture Organisation of the UN at the request of French officials to discuss the short and long-term response to the crisis.