New York state Attorney General Robert Abrams, one of the state's top vote-getters, announced he will seek the 1992 Democratic nomination for the Senate seat held by Republican Alfonse M. D'Amato.

D'Amato is under investigation by the Senate over allegations that he helped relatives, friends and major campaign contributors obtain preferential treatment from federal housing development officials.

Abrams said D'Amato has failed to meet the "standards of integrity" expected of a senator. Abrams said his election would mark a "return to the tradition of dignity" for New York's senators.

Abrams, 52, easily won reelection in November to a fourth, four-year term as attorney general. The former Bronx borough president said he was announcing his candidacy more than 18 months before the election because he needed time to raise money and organize support. D'Amato has $2.8 million on hand.

Also interested in a possible bid for the Democratic nomination are former vice presidential candidate Geraldine A. Ferraro, Rep. Robert J. Mrazek of Long Island, New York City Comptroller Elizabeth Holtzman and New York City Consumer Affairs Commissioner Mark Green. Holtzman lost to D'Amato in the 1980 Senate race while Green lost to him in 1986.

On the Republican side, Rudolph W. Giuliani, the former federal prosecutor who narrowly lost the New York mayoral race in 1989, may challenge D'Amato.