Soviet authorities, upset by the recent defection of five prominent Soviet artists, have been debating for four days whether to permit the Moscow State Symphony to make a five-week tour of the United States scheduled to begin in Carnegie Hall on Oct. 3 before coming to the Kennedy Center.

A representative of Columbia Artists, the booking agent for the tour, has been in Moscow since Monday trying to persuade the Russian authorities to change their minds after an apparent decision to cancel the tour.

Ronald Wilford, president of Columbia Artists, said yesterday that Tuesday he had thought the tour was definitely off and informed three universities in North Carolina where the orchestra was booked to perform that their performances would be canceled. But on Wednesday Wilford heard that negotiations had been reopened. Noting that the orchestra is scheduled to play in about two dozen cities between Oct. 3 and Nov. 4, Wilford added that no explanation for a cancellation had been given.

The orchestra is scheduled to play two concerts in the Kennedy Center. On Saturday, Oct. 6, at 8:30 p.m., Nathaniel Rosen, the American cellist who last year won first prize in the Tchaikovsky Competition in Moscow, is scheduled to play with the orchestra under the direction of Maxim Shostakovich, the son of the famous late Soviet composer. On Sunday night at 8:30, the soloist is to be pianist Dimitri Shostakovich, the son of the conductor and grandson of the composer.

While the State Department has no official role in arranging such tours, officials of the department began to suspect that the tour might be canceled when they were informed that the Soviets had told Columbia Artists that extraordinarily tight security precautions would be required if the tour is finally permitted.

A final decision is expected no later than tomorrow.