Thailand plans to remove nearly 1,000 Cambodian refugees from United Nations-financed camps and to place them in unofficial frontier settlements controlled by Cambodian guerrilla groups, Western diplomats here said.

Last week 230 Cambodians were quietly moved to the border. The relocations are aimed at refugee "illegals" -- people who entered long-established U.N. camps after Thailand officially declared them closed. Some foreign refugee workers feel that the moves amount to forced repatriation.

Diplomats said the Thai military may also try to root out illegals from U.N. camps set up to meet the Cambodian exodus last fall. They estimated this could involve 10,000 to 15,000 at the largest camp, Khao i Dang.

Bangkok representatives of the Office of the U.N. High Commissioner for Refugees said they had not objected to the Thai plans. "The people are being relocated within Thailand to areas in which they will continue to receive international aid," the spokesman said.

However, many Western embassies in Bangkok charge that the commissioner's office has ignored its mandate to protect refugees. They say many border settlements may be on Cambodian soil, and in any case are exposed to attack by Vietnamese troops looking for guerrillas.

Living standards are generally lower in these border camps. Many international agencies have no regular access, although they do supply food to the Thai Army for delivery.

About 280,000 Indochinese refugees are currently in U.N.-financed camps in Thailand. Refugee officials believe that only a fraction of that number could be resettled in other countries.

Diplomatic sources suggested that the hands-off attitude toward illegals on the part of the U.N. refugee commissioner's office may be intended to slow the continuing flow from Cambodia. Hopes for resettlement in the United States have brought many people to Thailand who in a legal sense are immigrants, not politically oppressed regugees, officials at the commissioner's office said.