A federal court hearing to discover who leaked the amount of a $500,000 settlement the American Broadcasting Co. agreed to pay a former employe in a sexual harassment case was suspended yesterday after one of the woman's attorneys charged that the figure was divulged by other lawyers assisting her in the case.

The hearing, before U.S. District Judge Barrington D. Parker, was held at the request of lawyers for ABC, who asked the judge to impose sanctions against whoever divulged the amount of the network's settlement with former employe Cecily Coleman.

The amount of the settlement, which was supposed to be kept secret, was reported in The Washington Post last Wednesday.

For the third day, the hearing was conducted behind closed doors at the request of Stuart Gerson, a lawyer for ABC. No plans were made yesterday for resumption of the hearing.

In the latest session, Mark Lane, one of Coleman's lawyers, said he believed the settlement amount was divulged by lawyers for the National Organization for Women's Legal Defense and Education Fund, which aided Coleman.

"I think it is quite clear as to what happened, who was responsible," Lane told Parker, while asking the judge to open the closed-door hearings. "I think it is outrageous that this agrement was breached."

Lane added, "I think it was breached by NOW and counsel for NOW and I think that closing these hearings just gives the impression that someone in this room did it, and it is not fair to those of us who are in no way involved in this and who have been aggrieved by this . . . . "

During yesterday's closed-door session Gerson questioned one of the NOW attorneys, Emily J. Spitzer.

Before the courtroom was closed, John Vanderstar, a lawyer representing both Spitzer and Marsha Levick, another NOW attorney, declined an offer by Parker to dispute Lane's allegations.

Parker's court docket said the hearings have dealt with a "motion for sanctions." Such sanctions are a form of punishment, such as holding lawyers and others in contempt of court or fining them for disobeying court orders. Out of court, Gerson said the hearings were "a search for truth . . . a search to determine the facts."

Before Parker closed the hearing again yesterday, Gerson told the judge that "the fundamental nature of that settlement was its confidentiality." He said that ABC, and particularly James D. Abernathy, the former ABC vice president Coleman accused of sexually harassing her, could be damaged further if the hearings were open to the public.

Gerson said the confidentiality of the settlement "was plainly breached and we are trying to figure out to what extent, and by whom and how . . . . "

Coleman, once executive director of ABC's voter-education program, contended in her lawsuit that Abernathy, her boss, had made repeated physical and verbal advances and "told her she could enjoy a promising future 'if she played her cards right.' " Coleman was fired after she complained about the allegations.

Both ABC and Abernathy denied all the charges.