NEW YORK -- Rep. Mario Biaggi (D-N.Y.), who rose from the city's police force to become one of its most prominent lawmakers, begins a fight for his political life today in the first of two criminal cases charging him with selling his influence to struggling federal contractors.

Biaggi, 69, is charged with accepting free vacations from one of his longtime political friends, former Brooklyn borough president Meade Esposito, 80.

In exchange, prosecutors will argue at the trial, Biaggi tried to help one of Esposito's clients, Coastal Dry Dock and Repair Co., an ailing firm in the Brooklyn Navy Yard.

Biaggi's indictment last March in the Coastal Dry Dock case was followed in June by charges that the Bronx Democrat engaged in extortion, racketeering, fraud and perjury in assisting Wedtech Corp., a small Bronx defense contractor.

In a 1986 wiretapped conversation between Biaggi and Esposito that prosecutors made public Friday, the two men coordinated stories after Biaggi had been questioned by the Federal Bureau of Investigation. "This is not a gift," Esposito said of the vacation trip. "It's, uh, it's a, uh, manifestation of my love for you."

Biaggi replied, "You didn't give it to me because I'm a member of Congress."

Faced with mounting legal bills, Biaggi has tapped his congressional campaign fund for $98,338 to pay three attorneys. Such personal use of campaign donations is legal for members who have been in Congress since January 1980, as has Biaggi.

The city's most decorated officer during his 24-year police career, Biaggi was wounded several times and still limps. He was close to winning election as New York City mayor in 1973 until it was revealed that he had invoked the Fifth Amendment before a grand jury after initially denying that he had done so.

That and several other investigations never led to charges against the 18-year House veteran, a leader on gun control and maritime issues.

Barry Slotnick, Biaggi's attorney, said the Coastal Dry Dock case was based on "an unfortunate indictment that never should have been brought.

"The government is going to try and prove that Congressman Biaggi and Meade Esposito had an illegal relationship," he said. "But their relationship was an up-and-up legitimate one. Congressman Biaggi wasn't accepting the trips as a quid-pro-quo for anything."

Biaggi has said the free vacation from Esposito was "strictly between friends" and "had nothing to do with politics or business." Esposito's lawyer, Ed Brodsky, said that "the government will not be able to prove that Meade Esposito is guilty of these charges."

Prosecutor Edward McDonald, head of the Organized Crime Strike Force in Brooklyn, declined to comment.

The case is based in part on wiretapped conversations between Biaggi and Esposito in which the congressman reportedly bragged that he was "doing wonders" for Coastal Dry Dock. Esposito is a partner in a Manhattan insurance firm that was owed $600,000 by Coastal Dry Dock, which, like Wedtech, has filed for bankruptcy protection.

Biaggi does not dispute that he urged New York Mayor Edward I. Koch and other city officials to cut the firm's utility rates or that he lobbied members of Congress and Navy and Coast Guard officials in an effort to win military contracts for Coastal Dry Dock and expedite payments to the firm. "That's the kind of service Congressman Biaggi has always provided," Slotnick said. "He did what every other congressman does."

Esposito is charged with secretly arranging payment of about $3,000 for Biaggi and a companion, Barbara Berlow, to visit the Bonaventure Spa and Hotel in Miami in December 1985.

At the time, Navy officials were contesting about $26 million in ship-repair bills submitted by Coastal Dry Dock.

Esposito is alleged to have disguised the $3,000 payment to Biaggi as a legal fee paid by a Long Island printing company that he formerly owned.

The indictment also charges that Esposito, once the undisputed Democratic kingpin in Brooklyn, arranged for a free vacation for Biaggi on a Caribbean island in 1984.

Biaggi is charged with obstructing justice by calling Esposito soon after being interviewed by FBI agents in June 1986 and allegedly urging him to give false information to investigators and a grand jury. If convicted, Biaggi faces as many as 32 years in prison and Esposito 27 years; both could be fined $250,000.