WASHINGTON – Republican Party officials said yesterday that President Bush will give up $6,000 in campaign contributions connected to disgraced lobbyist Jack Abramoff, joining an expansive list of politicians who have shed more than half a million dollars in tainted campaign cash.

The announcement came as Abramoff pleaded guilty in a second criminal case, acknowledging that he conspired to defraud lenders in the purchase of a fleet of Florida casino boats five years ago. The court appearance in Miami came a day after Abramoff pleaded guilty before a federal judge in Washington to defrauding Indian tribal clients of millions of dollars, conspiring to bribe members of Congress, and evading taxes.

Under plea agreements negotiated in the two federal cases, the once-powerful lobbyist promised to provide evidence and testimony in a wide-ranging Justice Department corruption probe of lobbying of Congress and federal agencies.

Fearful of adverse political fallout from the expanding investigation, Republicans in both houses of Congress moved forward with face-saving legislative packages to tighten lobbying regulations and begin to discourage dealings between lawmakers and influence peddlers. Rep. Jeff Flake, a Republican of Arizona, called again for a limit on “porkbarrel” projects in annual spending bills, which Abramoff himself described as “favor factories.”

Washington political leaders hope the legislative moves and campaign refunds will insulate their party as Abramoff begins cooperating with one of the largest congressional corruption probes in decades.

White House press secretary Scott Mc-Clellan said that Mr. Bush does not know Abramoff personally, although the two might have met at holiday receptions.

Abramoff raised more than $100,000 for the Bush-Cheney re-election campaign, making him an honorary Bush “pioneer.” But the campaign is giving up only $6,000 that came directly from Abramoff, his wife, and one of the Indian tribes the lobbyist represented. The money will be donated to the American Heart Association.

Mr. McClellan hotly contested any suggestion that Abramoff’s fund-raising won him any special favors or access.

“If someone thinks that money is coming in with strings attached, it doesn’t get in the door,” he said.

At least 24 politicians have now pledged to relinquish $515,199 in Abramoff-tainted campaign cash, including some of the most powerful Republicans in Washington. House Speaker Dennis Hastert, a Republican of Illinois, will give up at least $60,000. Mr. DeLay, the former House majority leader, has pledged to donate $57,000 in Abramoff-linked contributions to charity. And acting House Majority Leader Roy Blunt, a Republican of Missouri, plans to shed the $8,500 that Abramoff and his wife donated to his political action committee.

All but three of the 24 politicians getting rid of the funds are Republicans. The three Democrats -Senator Baucus of Montana, Senator Durbin of Illinois, and Senator Dorgan of North Dakota – have pledged to refund a total of $97,000 in contributions.