"Failure to quickly fund the Kenyan aid effort could lead to large-scale loss of life and the worst humanitarian crisis since Kenya gained independence (from Britain) in 1963," the charity said in a statement.

The Kenyan appeal, issued together with the World Food Programme and other UN organisations, said 396,525 tonnes of additional food assistance - valued at $221.5 million - was needed to avoid mass suffering for the next 12 months.

"Donor pledges are urgently required to avoid a break in food aid supplies in March 2006," a statement said.

Kenya is one of the worst-affected countries from a drought afflicting east Africa since late 2005. Scores of people and tens of thousands of livestock have died from starvation and related diseases in the arid northern regions.

Desperate searches for water and pasture have intensified clashes between Kenyan herders and pastoralists from neighbouring Somalia and Ethiopia.

"An estimated 3.5 million pastoral and farming people, including 500,000 school children, require emergency aid," the statement said. "The government of Kenya and its partners must act now to avoid a massive humanitarian catastrophe."

It said short rains which normally extend from October to December had failed, worsening the situation especially in the arid north and east of the country.

Oxfam said malnutrition levels had reached a dangerous 30 percent in the worst-hit areas, more than double the level at which an emergency is declared under UN standards.

"Unless there is swift intervention, growing numbers of people will become severely malnourished and the mortality rate will rapidly accelerate," Gezahegn Kebede, head of Oxfam in Kenya, said in a statement.