The United States, bowing to the wishes of its NATO allies, has unenthusiastically accepted a French plan for a new set of East-West disarmament negotiations centered on Europe, American sources said today.

The French proposal for a "Conference on Disarmament in Europe" may be given an official stamp of approval in Thursday's communique ending the current foreign ministers' meeting of the NATO alliance.

There terms and wording of a NATO endorsement for the idea are still under discussion with several capitals, including Washington, sources said. But whether or not it is mentioned in the NATO communique, the French idea is now expected to go forward on a carefully phased time schedule without objection from the United States.

European sources said the current version of the two-year-old plan calls for discussions with the Soviet Union to begin in connection with a follow-up meeting of the East-West Helsinki Conference to be convened in Madrid this November.

It seemed likely but not certain that West German Chancellor Helmut Schmidt would informally broach the matter to Soviet authorities when he is in Moscow next week for a meeting with Soviet President Leonid Brezhnev.

The Carter administration has been notably cool to another disarmament forum in a time of rapidly rising armament, especially a forum suggested by the often uncooperative French. But other European countries favored the plan, in part because of its appeal to political parties and public opinion upset by the new momentum in the arms race.

U.S. sources said lengthy discussions in Washington concluded that a new disarmament forum probably would do less harm to the Western alliance than would a U.S. policy of refusing to to along with European wishes.

There is a great skepticism among U.S. policymakers that progress can be made in such new talks, and some officials are not even convinced that the Russians will agree to the negotiations. Among the arguments made by those U.S. officials favoring the plan is a belief that new talks will demonstrate clearly to the Europeans how difficult it is to bargain on arms matters with Moscow.

Diplomatic maneuvering on the proposed disarmament forum came as Secretary of State Edmund Muskie appealed for unity in the NATO alliance to oppose the Soviet invasion of Afghanistan. He cited figures of a large-scale U.S. military buildup as an example of what must be done.

In a speech to a closed meeting of the NATO ministers, Muskie recalled that only a few months ago, when he was a U.S. senator chairing the Senate budget committee, the official estimate of U.S. military expenditures over the next five years was $800 billion. Now the five-year estimate has shot up to $1.25 trillion, he said.

As recounted to reporters by his spokesman, John H. Trattner, Muskie told the NATO ministers emphatically that the United States is not divided on the issues of Iran and Afghanistan, which he called "uniting influences" in America.

Muskie said the United States has now adopted "a low key, low-profile" policy on the Iran hostage crisis, which was not discussed at all in the NATO meeting until he brought it up at the end of today's session. He said the U.S. aim was to convince Iran that the hostages are more of a problem than an opportunity, and he reported that apparently some of the Iranian leaders are beginning to feel this way.

Muskie's discussion of Afghanistan was notable more for what he did not say than what he did. Despite reference by President Carter in Belgrade to possible "transitional arrangements" to facilitate Soviet withdrawal from Afghanistan and comments about the idea by presidential assistant Zbigniew Brzezinski, the secretary of state did not broach any such plan to the foreign ministers of the Atlantic allies, according to U.S. and European officials.