A Northwest Washington ballet instructor faces up to 50 years in prison after pleading guilty yesterday to five counts of taking indecent liberties with his dance pupils.

Karoly Barta, 46, a Hungarian-born dance instructor who runs a dance studio and who for the last four years produced Christmas "Nutcracker" performances at Constitution Hall, was ordered held without bond in D.C. Jail after entering his plea before Judge Fred B. Ugast in D.C. Superior Court. Under the provisions of the plea Barta did not admit committing any offenses.

Ugast, calling the case "a tragedy for these young girls and for Mr. Barta," set sentencing for Feb. 25 and told Barta he would reconsider his confinement order if Barta submits to psychiatric evaluation.

Barta, a short, slightly built former professional dancer, was indicted last April on 40 felony counts of engaging in, or attempting to engage in, sexual activities with nine girls ranging in age from 5 to 11 at his studio at 2801 Connecticut Ave. NW, formerly called Dance for Washington Inc., and recently renamed International Ballet Institute. Had he been convicted on all counts, he could have been sentenced to more than 200 years in prison.

In a plea arrangement with federal prosecutors, 35 of those counts were dropped in exchange for Barta's guilty plea to taking "immoral, improper and indecent liberties" with five pupils in incidents that occurred between 1978 and 1981.

Barta entered his plea under provisions of a 1970 U.S. Supreme Court decision allowing a defendant to plead guilty, therefore avoiding a trial, while at the same time not acknowledging that he committed any offenses.

In the 1970 case, North Carolina v. Alford, the defendant, facing strong evidence against him and a possible death penalty for first-degree murder, pleaded guilty to second-degree murder to avoid a capital sentence, but insisted he was innocent. The Supreme Court permitted this type plea.

Assistant U.S. Attorney Brooks Harrington, deputy chief of the felony trial division, said the government accepted this particular form of plea-bargain in Barta's case because it "provides for substantial penalties" while avoiding "the necessity of having the children go through the ordeal of testifying."

Assistant U.S. Attorney Harold L. Cushenberry, responding to Barta's failure to acknowledge that he committed the offenses, told Ugast that "there's nothing to show that Mr. Barta understands why he does these things . . . Something may trigger his actions that could endanger others."

In ordering Barta held, Ugast added that he was not convinced that the dance instructor and choreographer "is coming to grips with the problem."

Proffering to the court what the government would have shown had the case gone to trial, Cushenberry outlined complaints from five girls who said Barta fondled them while purporting to show them dance exercises.

Barta fondled the girls, Cushenberry contended, after taking them to private rooms while other dancers were rehearsing elsewhere in the dance studio. In one case, Barta fondled a 10-year-old he had encouraged to try out for the "Nutcracker" production after meeting her at the Watergate and telling her "she would be an ideal pupil," Cushenberry said.

According to Cushenberry, one 8-year-old told a grand jury she had been fondled by Barta but hesitated telling her parents "because I thought it was part of the dance instruction."

As part of the plea-bargaining process, Barta agreed not to contest the proffering of the prosecutor.

Barta's defense attorney, Gary Coleman, said in court that Barta's alleged sexual activities with young girls may have stemmed from "the pressure, the fantasy involved in the production of 'The Nutcracker.' "

Barta had staged productions of "The Nutcracker" at Constitution Hall since 1978. He had advertised a "Nutcracker" performance at the hall this year. But the week of dress rehearsals, parents of 10 pre-teenage dancers at a studio in Bowie pulled their children out of the production after learning through prosecutors of the charges against Barta.

The production fell through. Constitution Hall manager George Brooks said that "The Nutcracker" never had a firm engagement this Christmas.