Bronx County prosecutors, citing excerpts from long-secret FBI tapes and grand-jury testimony, detailed today their charges that Labor Secretary Raymond J. Donovan's construction company teamed up with a phony minority enterprise to defraud the New York City Transit Authority.

The chief of the prosecution team, Stephen R. Bookin, said in a 68-page document filed in Bronx Supreme Court that the alleged scheme included fabricated documents to make the minority company appear legitimate and an elaborate plan to mislead the transit authority into thinking that millions of dollars were being paid to the minority company while Donovan's company in fact retained them.

Donovan testified in related federal court hearings here last week that he had little to do with the contested dealings between his company, Schiavone Construction Co., and the allegedly fraudulent subcontractor, Jopel Contracting & Trucking, on a $186 million subway project started here in 1978.

The prosecutors disputed that contention with a long narrative, including alleged inconsistencies in Donovan's testimony over the course of several investigations, evidence that he visited Schiavone project sites "dozens of times" before joining President Reagan's Cabinet and assertions that he was well aware of underground loaders allegedly at the heart of the fraud.

Bronx authorities said they also had "witness testimony" that Donovan met with the head of Jopel, William Masselli, "numerous times during the progress of the job, at Prudenti's Restaurant in Queens, New York." They also asserted that Masselli "and others" met Donovan by prearrangement on a Miami Beach street in January 1979.

Donovan attorney William O. Bittman quickly denounced such allegations as "ridiculous, untrue and irrelevant." In a telephone interview, he said he had yet to study the prosecution's "supplemental bill of particulars" thoroughly, but said special prosecutor Leon Silverman's 1982 federal investigation had surely "demolished" talk that Donovan had ever been at Prudenti's.

Donovan has stated repeatedly that he met Masselli, a reputed member of the Genovese crime family, three or four times at most, and then always on the job site. Last week, Donovan said he also might have met Masselli at a football game.

The prosecution said Masselli formed Jopel in 1976 and, after discussions with two Schiavone executives, took over an excavation job from an earlier Schiavone subcontractor on a subway project in Queens.

In 1978, Schiavone Construction, in a joint venture, won the $186 million contract for a new subway tunnel and, prosecutors said, pledged to hire qualified, legitimate minority business enterprises (MBEs) and give them 10 percent of the work.

Instead, the prosecutors asserted, Schiavone Construction, after failing to get the transit authority to increase the contract to $189 million to cover the cost of the underground loaders needed for the job, entered into discussions with Jopel "to make it appear that Jopel was incurring the cost."

"The prosecution said Jopel's costs then could be added to its subcontract with Schiavone, which in turn could claim inflated billings by an MBE in its reports to the transit authority.

According to the prosecution, the plan agreed upon -- allegedly to give Schiavone the ancillary benefit of a tax write-off -- was for Schiavone to buy the underground loaders and, as Masselli stated on a Jan. 26, 1979, FBI tape, pretend to rent it to Jopel.

By May, the transit authority called for a hearing to determine "the bona fide status of Jopel."

The prosecution charged that "documents were created and testimony was rehearsed to deliberately mislead the New York City Transit Authority . . . . Documents were fraudulently backdated regarding the organization of Jopel, the officers, corporate meetings, ownership of stock certificates, capital contributions and the roles and duties of the principals . . . . Joseph Galiber a black state senator and Masselli's partner was not an owner of at least 51 percent of the stock, as required by statute. In fact, no stock certificates had ever been issued."