Fifty-four Vietnamese refugees were forced to leave for Japan today aboard the freighter that rescued them, a spokesman for the U.N. High Commissioner for Refugees said.

The refugees were among 66 Vietnamese rescued in the South China Sea by the Japanese freighter Chuwa Maru Saturday from their small, badly leaking fishing trawler. Twelve members of the group were accepted by the French government and were expected to fly to France soon.

Although Thai officials normally allow refugees to remain in the country until they are accepted by another country, they did not have time to process the 54 refugees before th Chuwa Maru was due to sail back to Japan, officials said.

One of the refugees, Tran Van Nghiem, 34, an English teacher, said the group had planned to leave Vietnam for two years, but extreme food shortages in Saigon finally prompted them to advance their plans.

According to Nghiem, long food lines form in the city as early as 2 a.m. and monthly rice rations have been cut from 20 pounds to as little as 2 1/2 pounds a person. He also said meat is almost unavailable.

His account confirmed reports by travelers to Hanoi of a severe food shortage caused by a drought gripping Vietnam since the winter.

Nghiem also described a thriving but risky black-market trade in food and medicine.

"People buy (rationed) rice for 150 piasters (20 cents) and sell it for 1,500 piasters ($1.80)," he said. But he added that black marketeering is punishable by five years in jail.