AUSTRALIA has become one of the top global donors to the famine in southern Somalia after Canberra announced an additional contribution of $20 million.

This, combined with another $20m of Australian aid funding reallocated by the World Food Program, takes the total contribution to $80m, second only to that of Britain.

The World Bank last night pledged more than $US500m ($462m) to aid the drought-stricken Horn of Africa region, as UN aid chiefs met in Rome to discuss ramping up relief efforts.

Foreign Minister Kevin Rudd visited the Somali town of Dolo to meet some of those seeking refuge and announce the additional funding.

"This will be five times as bad come the end of the year if we don't act now," he said.

The Australian position on funding sits in stark contrast to that of the US and many European nations, which have been reluctant to donate, fearing the aid will fall into the hands of the Islamist group al-Shabaab, which controls most of the drought-affected region in southern Somalia.

Al-Shabaab has previously refused to allow international aid agencies to deliver food and medicine but those restrictions appear to be easing.

Agencies including Medecins Sans Frontieres and the World Food Program are conducting limited operations in Somalia but are working in extremely insecure conditions.

The UN says it is still $350m short of what it needs to deal with the famine.

"As for the the US, the European Union and with all governments, I think it's important for everyone to step up to the plate," Mr Rudd said. "Six months' time will be too late."

Eleven million people are affected by drought in a crisis area about the size of NSW. Three million people are facing an acute food shortage.

World Food Program executive director Josette Sheeran said: "We have a triple crisis of this epic drought, conflict and then high food prices. In Somalia, food prices have soared over 240 per cent year after year.

"We need to scale up in areas like Dolo, which haven't been reached," she said.

The town of Dolo, close to the Ethiopian border, was said to be under the control of al-Shabaab only months ago, but now women and children are walking across the vast Somali desert for days and sometimes weeks to get here.

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