Famine has spread into one more region of Somalia and more than four million Somalis now need aid, the United Nations said Monday.

Hundreds of Somalis are dying every day, the UN Food Security and Nutrition Analysis Unit for Somalia found in its latest surveys. At least half of them are children.

About 750,000 more people may die from famine in the next four months if there is no adequate response, the UN report said, an increase of 66 per cent from July.

The top humanitarian official for Somalia described getting aid to the starving as a "race against time" and warned the famine would probably spread before the end of the year.

"This isn't a short-term crisis," said Mark Bowden, who heads the UN office coordinating humanitarian aid to Somalia.

Bowden said the four million Somalis needing aid represent more than half of Somalia's population. He said it is also an increase from 3.7 million Somalis who needed aid in July.

The southern Bay region is the latest area to be declared a famine zone. Nearly 60 per cent of people there are acutely malnourished — four times the rate at which an emergency is declared, said Grainne Moloney, head of the food security unit.

"I've not seen anything like it," said Moloney.

Famine in 6 areas

Famine has now affected six areas, including four southern Somali regions and two settlements of internally displaced people.

The UN says tens of thousands of people already have died in Somalia due to the severe violence, drought and famine. More than 150,000 refugees have sought aid in the last few months. Families in Kenya, Ethiopia and Djibouti have also been affected.

Somalia has been hit hardest, its problems compounded by more than 20 years of civil war and Islamist insurgents that banned many aid agencies, including the UN's World Food Program, from their territory.

Maloney said a bad drought meant that harvests there are a quarter of normal levels — the worst for 17 years. The price of a day's casual labor had dropped from 15 kilograms of cereal to three kilograms, she said.

Bowden said access to areas in the south held by the al-Shabab insurgent militia was improving, and that there were some aid agencies that were able to work there.

"There's a far greater level of coverage than we anticipated," he said.

The UN food agency was concentrating on the areas of Somalia it did have access to — about 1.9 million people — and encouraging donors to fund other agencies who had access to southern areas, spokeswoman Challiss McDonough said.