The delay will give the two more time to cooperate with investigations into official corruption in Washington and the 2001 murder in Fort Lauderdale of businessman Konstantinos "Gus" Boulis, who was killed a few months after selling SunCruz Casinos to the pair.
U.S. District Judge Paul C. Huck agreed to a motion from prosecutors and defense attorneys to delay the start of their prison terms to Oct. 2. Both men had been ordered to report to prison by next Thursday.
Abramoff and Kidan were sentenced earlier this year to just under six years after they admitted concocting a fake $23 million wire transfer to make it appear that they were contributing their own money toward the $147.5 million SunCruz purchase.
Based on that false transfer, lenders Foothill Capital Corp. and Citadel Equity Fund Ltd. gave the pair $60 million in financing.
U.S. Attorney R. Alexander Acosta's office declined to comment on the extension. Defense lawyers did not immediately respond to a call and an e-mail seeking comment.
Abramoff has also pleaded guilty to three charges as part of a broad corruption probe involving members of Congress and aides. David Safavian, formerly the top procurement officer for the Bush administration, was convicted Tuesday of covering up his dealings with Abramoff.
In the Boulis case, Kidan and Abramoff have both denied any role in the businessman's killing. Kidan told investigators in May he believed Boulis was killed by an associate of former New York organized crime boss John Gotti. That associate, John Gurino, was killed in 2001.
Three other men are charged with first-degree murder in the Boulis case and could face the death penalty if convicted. All three have pleaded not guilty.