The New York City Ballet has refused to return to the Kennedy Center this year because George Ballanchine believes the Opera House's stage floor is too hard, and dangerous to his dancers.

The 77-year-old Ballanchine said last night he has informed the Kennedy Center that "until they fix that floor we are not coming back."

Kennedy Center Chairman Roger ystevens confirmed that the NYCB told the Kennedy Center several days ago that the company, which has been a regular feature of the ballet season, will not perform here in 1981.But Stevens said that Balanchine indicated the troupe would dance at the Opera House in 1982 if the floor is renovated.

"The floor is terrible and we lose people -- they get injured. We return when they fix the floor," Balanchine said in his typically fractured English. w"Now, it's like running horses on pavement" for dancers to perform on the Opera house stage.

Stevens said last night that Balanchine has "made a big fuss" over the floor, which was originally constructed "the way the dance crowd wanted it," but which has since suffered deterioration of the spring-and-wood super-structure.

Stevens said he first learned of the NYCB's dissatisfaction with the stage last fall. But Balanchine has voiced complaints about the floor at least since October 1979, and other dance companies have been complaining about it since shortly after the Center's opening in 1971. An experimental floor covering was tested in December by dancers from the NYCB and the American Ballet Theatre and found acceptable, according to Stevens. But the new floor has never been used in performances.

"Everybody else dances on that floor," said Stevens. "ABT is perfectly happy with it. NYCB dancers said it was all right . . . but if the NYCB didn't want to come back we're not going to get down on our knees and beg them. We lost a lot of money on them every year."

The Kennedy Center chairman explained that nonetheless the floor will be reconstructed in time for NYCB to give a Washington season in 1982.

Meanwhile, Balanchine announced that the NYCB will present a 10-day marathon festival in a tribute to composer Peter Tchaikovsky beginning June 4 and featuring new and existing ballets choreographed to the composer's music.

A NYCB spokeswoman said that the choreographers whose works will be represented at the festival are: Balanchine, Jerome Robbins, Peter Martins, Jacques d'Amboise, John Taaras and perhaps Joseph Duell. In addition, a ballet choreographed to Stravinsky music may be presented during the festival.

Asked at a press conference yesterday why he decided to do a Tchaikovsky festival, Balanchine said, "He was a friend of mine [Tchaikovsky died before Balanchine was born] and I talk to him on the telephone and he says you have to do it." The response drew howls of laughter.