WASHINGTON  Bush administration officials said Tuesday that they were confident that charges against six suspected members of Al Qaeda would survive expected defense contentions that the cases are based on unreliable statements obtained using harsh interrogation methods.

The officials confirmed that the Justice Department and the Pentagon, aware of probable legal challenges involving possible mistreatment of prisoners, began an extensive effort in late 2006 to rebuild the cases against the six men using what officials called “clean teams” of agents and military investigators.

By interviewing the prisoners again, and reassembling other evidence against them, the prosecutors could present evidence in court that would be harder for defense lawyers to challenge. But some legal experts said that approach might not defuse defense arguments that the initial investigations were tainted.

The chief military prosecutor for detainees held at Guantánamo Bay in Cuba, Col. Lawrence J. Morris of the Army, declined to discuss the details of how prosecutors would deal with questions about the treatment of captured terrorism suspects. But, Colonel Morris added, “we will take very seriously our burden to present trustworthy evidence on which a panel can rely” in reaching a verdict.