NEWARK, N.J. (AP) _ A casino union official was sentenced today to 10 years in prison and fined $10,000 for his role in a conspiracy to use the office of former Atlantic City Mayor Michael Matthews to benefit organized crime and businesses in return for payoffs.

''There is no doubt in my mind that you were part of a mob organization,'' U.S. District Judge Harold Ackerman told Frank Lentino.

The 73-year-old defendant is a business agent for Local 54 of the Hotel and Restaurant Employees and Bartenders Union, and government attorneys have described him as a close associate of the Philadelphia-southern New Jersey organized crime family allegedly headed by Nicodemo Scarfo.

Lentino pleaded guilty Oct. 29, the day his trial was to begin, to conspiring with Matthews and reputed organized crime associates.

He showed no emotion as the sentence was announced.

Matthews and Lentino were indicted together March 27 on extortion and conspiracy charges.

On Monday, Ackerman sentenced Matthews to 15 years in prison and fined him $10,000. He had pleaded guilty midway through his trial to accepting $10,000 from a federal undercover agent.

Federal authorities said the payment was in return for Matthews' promise to clear the way for the sale of city-owned, casino-zoned land to an FBI-created real estate company.

Matthews said he assumed the money was a campaign contribution.

The broad conspiracy count to which Lentino confessed included allegations that a federal undercover agent paid $8,000 to Lentino and the Scarfo organization to win a contract for an FBI-created chemical company.