NEW YORK, NOV. 5 -- Rep. Mario Biaggi (D-N.Y.), after denying wrongdoing in a voice choked with emotion, was sentenced today to 2 1/2 years in prison and fined $500,000 for accepting an illegal gratuity and obstructing justice.

Biaggi's sentence was stayed pending appeal. He will remain in Congress while the House ethics committee weighs disciplinary action, but he has not voted since his conviction.

In a Brooklyn courtroom, U.S. District Court Judge Jack B. Weinstein said that, while he admired Biaggi's career as a much-decorated police officer and a member of Congress for 19 years, the Bronx Democrat is guilty of "greed and arrogance" for taking free Florida vacations from a longtime political friend.

Biaggi, 70, speaking to reporters after closeting himself with his four children, said he was "terribly upset" at the sentence. He challenged Weinstein's description of him as the fallen hero in a Greek tragedy.

"I haven't fallen," Biaggi said. "I've been smitten, but I haven't fallen. I don't believe in my heart I've done anything wrong."

But Edward McDonald, chief of the Justice Department's Organized Crime Strike Force in Brooklyn, chided Biaggi for having the "audacity" to invoke his wife's failing health in a plea for leniency.

Noting that Biaggi visited a Florida spa with model Barbara Barlow, 45, while his wife was suffering from Hodgkin's disease, McDonald said the defense had portrayed Biaggi as "an aging Romeo unable to control his urges" but now calls him a "devoted husband" who should not be imprisoned.

Biaggi was convicted in September of accepting free vacations from former Brooklyn Democratic leader Meade Esposito, 80, in exchange for using his influence to help a ship-repair company that was a major client of Esposito's insurance agency. Biaggi lobbied several federal and local officials on behalf of the firm, Coastal Dry Dock and Repair Co.

Weinstein, citing Esposito's poor health, gave him a suspended prison term last month and fined him $500,000.

Biaggi was convicted on three counts but acquitted of more serious bribery and conspiracy charges. The obstruction-of-justice charge involved a June 1986 call in which Biaggi urged Esposito to lie to investigators. In the wiretapped conversation, Esposito agreed to say that the free trips for Biaggi were "a manifestation of my love for you."

The former policeman, who walks with a cane because of old injuries, still faces a second corruption trial involving his assistance to Wedtech Corp., a small Bronx defense contractor.

Weinstein today rejected an argument by House counsel Steven Ross that one count, charging Biaggi with crossing state lines to commit a crime, should be set aside because of congressional immunity. Ross said Biaggi was performing official business by visiting a Florida health clinic.

But Weinstein called this "an afterthought" and said the same logic could be used to protect a member of Congress who murdered someone in Florida, then claimed he was on official business because he was on the fisheries committee and went fishing there.

Biaggi's lawyer, Barry I. Slotnick, cited hundreds of letters supporting his client, including one from House Speaker Jim Wright (D-Tex.). He recounted Biaggi's rise from "abject poverty" and said the conviction had caused him "public humiliation and shame."

Biaggi then addressed the judge in a halting, barely audible voice. "Your honor, the only thing I did was accept some hospitality from an old friend," Biaggi said. He said he kept asking himself, "Why am I here? What did I do wrong?"

Prosecutor McDonald responded that "Mario Biaggi has disgraced himself and disgraced his public office . . . . He has demonstrated himself to be a thoroughly corrupt, venal individual."

Weinstein said Biaggi "does not fully appreciate" the gravity of his offense. The judge said lawmakers must be held accountable under the laws they write, notwithstanding a letter he received from a congressman, whom he did not identify, defending Biaggi on grounds that it is a "common congressional practice" to accept free trips.

Weinstein, who could have sentenced Biaggi to a maximum of 12 years, said he took account of Biaggi's age, health problems and "good deeds." He gave Biaggi two other one-year prison terms to run concurrently with the 2 1/2-year sentence for obstructing justice.