The International Monetary Fund yesterday announced that it will lend Vietnam approximately $28 million to assist its economic recovery from the long years of fighting that ended in 1975 with the victory of the communist side.

Although the loan is not the first made by the IMF to Vietnam, it could provoke protests in Congress and elsewhere in the United States from opponents of aiding the Vietnamese regime.

Since the United States provides approximately 20 per cent of the IMF's funds, critics of U.S. aid could argue that the loan constitutes a "back door" means of channeling U.S. assistance to Vietnam.

Efforts already have been made in Congress to prohibit the use of U.S. contributions to international lending institutions like the IMF and the World Bank in aiding certain communist nations and other countries that are alleged violators of human rights.

However, the Carter administration has resisted such moves on the grounds that they constitute a political interference that would prevent these institutions from performing their specifically assigned economic missions.

Since Carter became president, the United States has used its votes in some international lending agencies like the World Bank and the Inter-American Development Bank for political purposes, specifically in instances involving human-rights considerations.

But U.S. sources say, the administration has refrained from using its vote in the IMF politically. As a result, that agency has made loans recently not only to communist countries like Vietnam but also to nations like Chile, Zaire and South Africa that have been attacked for their poor human-rights records.

The purpose of the 131-nation IMF is to help member countries overcome financial problems caused by balance of payments problems. Bank sources said that, as a member Vietnam qualifies for such aid, provided that IMF's directors determine it is taking the necessary steps to overcome its payments problems.

The loan announced yesterday brings the total of IMF aid to Vietnam to approximately $57 million. The IMF said the newest loan is intended to ease the drain on Vietnam's foreign exchange reserves caused by its need to import large amounts of food in the past year.

In a related development, a Japanese newspaper yesterday quoted a Vietnamese official as saying his country is willing to resume talks with the United States on normalizing relations without any preconditions.

In an interview with The Mainichi Shimbun Vice Foreign Minister Phan Hien said: "We are prepared to resume talks with the United States. We believe normalization of relations between Vietnam and the United States will be of benefit to all of Southeast Asia."

Past U.S.-Vietnamese talks on establishing diplomatic ties have made no progress. Vietnam has insisted that the United States follow through on its pledge to make large financial contributions to rebuilding the country, and the United States has demanded more information about Americans missing in Vietnam.

State Department spokesman Hodding Carter said yesterday that he had no comment on the Phan Hien statements. he reiterated past U.S. statements about Washington's willingness to discuss the diplomatic-recognition question with Hanoi, but added that he was not aware of any talks "being imminent."

U.S. and Vietnamese representatives are scheduled to meet soon in Hawaii to discuss methods of identifying and returning the bodies of Americans in Vietnam.