Ministers from dozens of nations debated rival plans for a southern Asia tsunami warning system today, as the United Nations called on countries to make good on pledges of aid to sustain the massive relief effort for last month’s disaster.

Camps for up to 500,000 tsunami refugees will be built on devastated Sumatra island, the UN said today.

World leaders and aid workers were preparing today to co-ordinate the distribution of billions of dollars in aid to countries hit by the worst natural disaster in decades.