Most have fled from a brutal, decades-long campaign by the Myanmar military against Karen and other ethnic minority rebels. They are housed in a string of camps along the frontier.

Part of a surge in worldwide food prices, rice has increased by 50 percent in the past two months and some experts predict further hikes of up to 40 percent. Meanwhile, the U.S. dollar continues to slide against the Thai baht currency.

Dunford, executive director of the Thailand Burma Border Consortium, said he would need to make up a budgetary shortfall of US$5.8 million (€3.7 million) to keep up the already inadequate level of food rations. Together with distributions of building supplies, soap and mosquito nets, those rations were cut earlier after a drop in donor funding.

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If the gap is not filled, refugees could be issued with just 12 kilograms of rice (26 pounds) a month and no other food items — less than half of their daily protein and calorie needs, he said. Nursery school feeding and health projects would have to be slashed or terminated.

“This is a very vulnerable group of people under threat,” Dunford said.

The consortium, which has been assisting the refugees for nearly 24 years, is made up of 11 Christian and other aid organizations and is funded mainly by the U.S. and European governments.

Dunford said he was appealing to his funders as well as the Thai government, which has refused to allow the refugees to seek meaningful employment outside the camps.

Some donors, Dunford said, have shown reluctance to continue funding a refugee population that has little prospect of sustaining itself or returning home. Following the pro-democracy uprising in Myanmar late last year, others have focused on increasing humanitarian aid inside the country rather than along the frontier.

In a related development, the U.S.-based group Refugees International urged the international community Wednesday “to address the humanitarian needs of Burma’s 55 million people in the absence of political progress.”

A report by the private group criticized the U.S. government for maintaining restrictions on humanitarian assistance in the belief that any aid props up the ruling junta.

European governments, it said, have over the past year changed a similar policy to one of greater humanitarian aid together with sanctions specifically targeted against the regime’s economic activities.

It also urged more help to agencies working with refugees in Thailand and providing cross-border assistance to tens of thousands of people displaced from their villages by the conflict.