A Bronx prosecutor charged today that special federal prosecutor Leon Silverman cut off grand jury inquiries in 1982 into the legitimacy of a minority firm that was working for Labor Secretary Raymond J. Donovan's construction company.

"He Silverman instructed the grand jurors not to be concerned with this because it was not within their mandate," Bronx prosecutor Stephen R. Bookin testified at a federal court hearing here. "Questions by the jurors were stopped."

Donovan and nine other men were indicted in the Bronx in September on grand larceny and fraud charges stemming from dealings between Donovan's firm, Schiavone Construction Co., and the allegedly fraudulent minority company, Jopel Contracting.

Jopel was run by William P. Masselli, who has been indicted for murder in what Bronx authorities say is one of several gangland slayings related to the case.

The disclosure of Silverman's restrictive action came during the second day of hearings on an attempt by Donovan's lawyers to have the charges against the labor secretary moved out of state court.

Donovan's attorneys have been contending that "the broad scope" of Silverman's inquiry into Donovan's relationship with Jopel and Masselli had cleared the air on that score and served to demonstrate the "hostile" and partisan nature of the Bronx indictment.

Bronx District Attorney Mario Merola and his aides previously have contended that Silverman's investigation was "not thorough enough." Today's testimony, however, represented the first official disclosure of the limits he had placed on it.

Silverman could not be reached for comment.

He concluded at the time that there was "insufficient credible evidence" to warrant Donovan's prosecution for any federal crime. He also suggested in his report that there was nothing improper in the "relationship between Jopel and SCC [Schiavone Construction Co.]"

The chief of the Bronx state prosecution team, Bookin took the stand this morning in an effort to demonstrate that the case against Donovan was based on a conspiracy begun in 1979, long before he became labor secretary.

But under prodding by Donovan lawyer Paul Curran, the session turned to some of the explosive issues of the drawn-out Donovan investigations.

Cross-examining Bookin this afternoon, Curran cited some of the segments of the Silverman report that dealt with Masselli's work as a Schiavone subcontractor on a $186 million New York City subway project.

At one point in the report, Curran emphasized, Silverman declared that "a two-day search of Jopel records in the possession of the U.S. attorney for the Southern District of New York failed to disclose any documents suggestive of anything other than a straightforward business relationship between Jopel and SCC."

Bookin said he did not know what documents Silverman was talking about, but Bookin said he knew of other records indicating that Silverman's inquiry had been less than thorough.

The Bronx prosecutor said records of the Silverman grand jury, which sat in the Eastern District of New York, based in Brooklyn, showed that Silverman told the jurors not to bother about "whether it Jopel was a legitimate minority business enterprise."

According to Bookin, Silverman also told his grand jurors not to be concerned about dealings between Jopel and Schiavone Construction Co. and to focus instead on whether Donovan had told the truth at his Senate confirmation hearings in 1981. The questioning about Jopel and Masselli at those hearings was not extensive.

In any case, Bookin said that Silverman instructed them only to consider whether Donovan had been untruthful in his testimony before the Senate in 1981. "Questions by the jurors were stopped," he said. "He ended that inquiry in the grand jury because he felt at that time that it was not within his mandate."

The hearings here were adjourned until Monday amid a hubbub over the records of the Bronx grand jury, which voted to indict Donovan Sept. 24, just a few hours after he testified before it.