The locked-out dancers of the American Ballet Theatre last night rejected management's latest offer by a vote of 69 to 0. Their spokesman, Frank Smith, claimed that ABT had "double-crossed the dancers." s

Smith referred to informal negotiating sessions between the attorneys for the dancers and for management -- negotiations which he said, had resulted in a contract proposal acceptable to the dancers.

Dancers' attorney Leonard Leibowitz explained that he and Alan Jaffe, the attorney for ABT, had worked out a proposal that the attorneys would attempt to "sell" to their respective clients.

The dancers were willing to accept that proposal, Leibowitz stated, but ABT's executive committee was not. Leibowitz was informed of this only 2 1/2 hours before the dancers were to meet. The ABT attorney made a new offer -- and it was that offer which the dancers rejected.

During the dancers' meeting yesterday, Leibowitz repeatedly emphasized that a "no" vote would mean cancellation of the troupe's upcoming cross-country tour and result in the dancers being out of work for months to come.

The understanding that Leibowitz said he had reached with ABT's lawyer calls for a 50 percent wage and fringe increase over three years. The revised offer, he said, represented an approximate 40 percent increase, and lacked various key items, including a job-security guarantee.

ABT officials could not be reached early this morning.

Late last week, when the attorneys met, sources on both sides said they anticipated a quick settlement in the seven-week-old lockout.

"It seems to be some kind of moral bad faith," Leibowitz said. He said the dancers would no longer participate in informal negotiations.