Justice Department officials, accused by Democratic congressmen of moving too slowly on prosecuting savings and loan cases, say they have identified what they believe to be the top 100 cases of financial fraud and given them priority.

U.S. Attorney General Dick Thornburgh said in an interview this week that about 20 of those cases account for 80 percent of the suspected fraud at thrift institutions. He said most of the cases are concentrated in Texas, Southern California, New York and Florida, with other cases scattered throughout the country.

Though the local FBI offices and many U.S. attorneys have been clamoring for more resources to handle an avalanche of criminal referrals, FBI officials said recently that they have enough agents now to tackle the biggest cases.

"We could apply more resources if they were available, but we have the manpower now assigned to cover the significant cases," said Bill Baker, assistant FBI director in charge of criminal investigations. "We have earmarked the top 100."

Two weeks ago, faced with growing Democratic criticism over the pace of prosecutions, the Bush administration announced it no longer opposed congressional efforts to double the funds for investigations to $100 million for next fiscal year. The Justice Department is already hiring 118 prosecutors and 210 agents with $50 million made available late last year.

A Justice Department survey conducted in March 1989 showed that because of lack of resources, the FBI had opened but was not actively pursuing more than 1,300 cases of suspected financial fraud involving more than $100,000. The FBI reported 4,100 active investigations of fraud involving more than $100,000.

FBI and Justice Department officials said this week that the number of "pending but inactive" cases had changed, but they could not give a new figure.

Officials from the Office of Thrift Supervision, which regulates thrifts and had helped develop the list of 100 top cases in recent weeks, said before then that the Justice Department did not know which cases regulators believed to be most important. The list should help focus investigative efforts, OTS officials said.