Tens of thousands of people already have died in Somalia, Kenya, Ethiopia and Djibouti, according to the United Nation.
The UN estimates that more than 12 million people in the region need food aid, according to the UN.
In Somalia alone, 1.4 million children are affected, an estimated 390,000 are suffering from malnutrition, and nearly 140,000 in the south-central region are facing imminent death from "severe acute malnutrition".
Somalia, which has been engulfed in conflict for nearly two decades, has been hardest hit, with famine raging in five regions.
The southern and central parts of the country, which are mainly under control of al-Shabab extremists, have been worst affected because of the Islamic group's refusal to allow key humanitarian organisations to deliver aid. Among the groups that have been blocked is the UN World Food Programme, the world's main aid provider.
Donors have contributed more than US$1 billion ($1.2 billion) to help famine victims, but UN Secretary-General Ban Ki-moon appealed again for US$1 billion more.
"Humanitarians are on the ground saving lives," he said. "But we are still not reaching all the people who need our help, and the crisis has still not peaked."
- HERALD ONLINE, AP