UNITED NATIONS — Taiwan made an unprecedented bid for U.N. membership over the weekend and was immediately rejected by the world body’s legal department. The bid, made in a letter to Secretary-General Ban, was another step in a series of attempts by President Chen and his government to gain international recognition.

Earlier this year, Taiwan attempted to become a full-fledged member of the World Health Organization, after failing in a bid for observer status there. In his letter — delivered by hand to Mr. Ban late last week by U.N. ambassadors from Swaziland and the Solomon Islands — Mr. Chen for the first time requested “the admission of Taiwan as a member” of the international organization.

The bid, however, “could not be received and was thus returned by the United Nations Office of Legal Affairs,” a U.N. spokeswoman, Marie Okabe, told reporters yesterday. The legal decision was based on a 1971 General Assembly resolution that declared communist China “the only lawful representatives of China” at the United Nations,” she added.

“We will never give up,” the press director at the Taipei Economic and Cultural Office in New York, Ben Shao, said. The 1971 resolution that addressed China did not refer to Taiwan, he noted, adding, “There is a group of 23 million people whose voices cannot be heard,” he said.

The ranking Republican on the House Foreign Relations Committee, Rep. Ileana Ros-Lehtinen of Florida, said during a visit here yesterday that “courageous” Taiwan deserves U.N. representation. She acknowledged, however, that the State Department was unlikely to change its “one China” policy, which bars a unilateral change in the country’s status.