In a major management change at the Kennedy Center yesterday, Martin Feinstein -- for eight years the Center's executive director -- relinquished that position to become the Center's director of opera and ballet.

Simultaneously, Christing Hunter, president of the Washington Opera Board, said that Feinstein had accepted the position of director of that company, effective Jan. 1. He will succeed George London, whose retirement was announced last week.

Feinstein's present contract with the Kennedy Center -- which still has a year to run -- was renegotiated yesterday morning. Former Supreme Court Justice Abe Fortas was involved in the renegotiation. No details of the new contract were available yesterday.

The position of executive director, which carried a salary of $72,000, will not be filled, Center board chairman Roger L. Stevens said yesterday in announcing the change. When asked who would be responsible for such special events as the festival the Center has presented each year, he added, "We will have to add some new people."

Feinstein confirmed that his combined salaries from the Center and the Washington Opera will exceed $100,000 yearly -- and that in addition, he is free to do outside consulting for additional fees.

It is widely known that Feinstein has for several years argued for a vastly extended opera program in the Kennedy Center.But an annual projected budget of between $5 million and $8 million brought a resounding veto from the Center's board.

The program of summer opera Feinstein introduced in the Center's Terrace Theater this year -- which enjoyed general critical acclaim -- ran up a deficit at least $100,000 over the projected deficit.

In his new post, Feinstein, 58, will be responsible for planning all the opera and ballet that comes to the Center. This will include not only the Washington Opera, but such visiting troupes as the Metropolitan Opera next spring and, if financial and logistical problems can be worked out, a return visit by the Bolshoi company from Moscow.

Stevens said he had urged Feinstein to make the move to the Washington Opera, because "the new arrangement will permit Martin Feinstein to concentrate upon opera and ballet, two areas in which he has made great contributions."

Feinstein said yesterday that "It is no secret that I have felt for some time that there should be further development of opera in Washington, which is the only major capital in the world that does not enjoy an extended opera season.

"Although the Washington Opera currently offers only 16 performances a season, I hope that in the future we will be able to have many more superb performances."

The change in Feinstein's position became almost inevitable two weeks ago, after an executive committee meeting of the Kennedy Center board, according to two members at the meeting.

Harry McPherson, general counsel for the Center, said yesterday that two of the principal subjects discussed at the meeting were budget deficits and the desirability of increasing the amount of American-born ballet and opera presented at the Center.

Another member of that committee confirmed that two "factors" leading to yesterday's action were "losses and deficits" and a determination that "in programming we were going to put more emphasis on American things."

Feinstein said those two subjects "were never discussed with me," and that he was present at only part of the meeting.

"It was part of a discussion of where the Center is going to go from here," the member said, "and this was related to the economic results of some of the things we had been doing and my impression was that Martin had a good deal to do with this."

The member traced the developments back to a proposal by Feinstein "two years ago" for an ambitious National Opera based at the Center. "Opera is much more expensive than putting on a play and all opera companies are losing money. If we went into something of the magnitude of a National Opera, I don't think we have the money and, furthermore, I don't think we have the support. But as to what we will do in the future, I think the summer opera will continue and I think we'll let the Washington Opera continue to perform our opera."

Asked if Feinstein's new title of director was set at the executive committee meeting, the member recalled that no title was mentioned, and that Feinstein's future role at the Center was discussed in the context of Feinstein's becoming "a consultant."

Of his plans for a National Opera company, Feinstein said he had never made a formal presentation to the board, and would not have made one until a bond issue to finance the proposal was agreed upon and a full budget was ready for presentation.

Christine Hunter said, "The Washington Opera is a company with ambitious plans, and Mr. Feinstein's leadership will be an important ingredient in their realization."

Feinstein came to the Kennedy Center early in 1972, a few months after it opened. Prior to that time, he had been Sol Hurok's lieutenant in the New York offices of Hurok Attractions, where he served as second in command to the famed impressario.

During his years at the Center, Feinstein has been instrumental in bringing to Washington the Bolshoi Opera from Moscow, the Deutsche Oper from West Berlin, the Paris Opera and La Scala from Milan. The forthcoming visit of the Vienna State Opera is another of his achievements.

Feinstein has also been the planner behind the Kennedy Center festivals built around Shakespeare, Haydn, The New and The Old, and last spring's romantic Parisian series, which proved a financial disaster. Under his direction, every major ballet company has danced in the Opera House.