Soviet television has agreed to broadcast an hour-long discussion this month between American and Soviet physicians on the medical effects of nuclear war, the American sponsors said yesterday.

Dr. James E. Muller of Harvard University Medical School said approval had been received from Moscow for the joint program to be taped there June 24 and broadcast in prime time on Soviet television June 26. Muller was in Washington yesterday to discuss plans for the unusual event with officials of the State Department.

Muller, Dr. Bernard Lown of Harvard's School of Public Health and Dr. John O. Pastore of Tufts University School of Medicine will be the American representatives on the broadcast. They are officers of the group that proposed the event, International Physicians for the Prevention of Nuclear War Inc., which is reported to have affiliates in 20 countries.

The chief Soviet participant in the activity of the international panel, and an expected participant on the television program, is Dr. Eugene I. Chazov, head of the Kremlin clinic that treats Soviet leaders and, reportedly, personal physician to President Leonid Brezhnev.

President Reagan, in an address to the British Parliament Tuesday, proposed that he appear on Soviet television in return for an appearance by Brezhnev on American television. No progress in implementing this has been reported.

Muller said that no reciprocal arrangement involving U.S. television has been worked out in connection with the nuclear war discussion, but that the sponsors have been in touch with the American networks, which have shown interest.

According to the plan of the American sponsors, topics to be covered in the broadcast include immediate and long-term effects of nuclear explosions, medical care for war victims, the economic and psychological costs of the arms race, accidental nuclear war and the question of limited nuclear war.

In 1972, at the height of detente, President Nixon spoke on Soviet television. A year later Brezhnev spoke on American television. But television exchanges between the two nations have been rare.

The State Department said late yesterday that it neither encourages or discourages the physicians' Moscow plans. "Our view would depend on the content of the program as it is actually presented to the Soviet people," a spokesman said, adding that "pitfalls" of Soviet editing and translation had been pointed out to the physicians.