The United States was strongly criticized by other member nations of the Inter-American Development Bank--including industrialized countries in Europe and Japan--when it blocked funds for a Nicaraguan road-building project late last month, according to the unpublished minutes of a meeting of the IDB Board.

In what one source described as a departure from the usually muted language of the board's meetings, several board members were outspoken in their disapproval of the U.S. position, the minutes of its June 22 meeting show. The report obtained by The Washington Post was in English, translated by the IDB from the original Spanish.

The representative of a group of nations including West Germany, Britain and Italy described the U.S. opposition to release of $2.2 million to Nicaragua to finish the project as an "attempt to evade the ideal" of the IDB, which is supposed to lend money to "promote the material and social development of the poorest people" in developing countries. The U.S. veto "causes damage above and beyond the purely material aspect" of the loan, Carlo Binetti said.

The administration has said that it will oppose any loan to Nicaragua from the World Bank and its affiliates and from the Inter-American Development Bank until the Sandinista government makes major changes in its domestic economic policy. Treasury official James Conrow described this position on June 30, the day after the formal vote on the proposal to grant Nicaragua the $2.2 million. An administration official yesterday said that this has been official U.S. policy since February 1982.

All of the Inter-American Bank's other 42 members supported the road-building loan for Nicaragua when the formal vote was taken on June 29. But the United States commands a veto on loans such as this one, which are made by the bank's Fund for Special Operations, at low interest rates. The United States was outvoted in an IDB meeting on July 6 when the board approved a $500,000 loan to Nicaragua that was not from this special fund.

The representative for Bolivia, Paraguay and Uruguay at the June 22 meeting rejected the view that U.S. opposition was on economic grounds. Luis M. Pigurina said, "we consider it undesirable in an institution such as this one or the World Bank for decisions to be made on the basis of political motives in economic disguise."

The U.S. representative at the June 22 meeting was Ira Kaylin, a Treasury Department official who was standing in for the U.S. Executive Director to the Board. He said briefly "the United States cannot support this proposal. We continue to believe that the current macroeconomic policies of the government of Nicaragua are not conducive to economic development."

An Inter-American Development Bank official yesterday said that during former president Carter's term of office, the United States was accused of voting on political grounds against countries deemed to be violating human rights. The bank's charter requires members to vote on economic grounds only.