The Republican leaders of the House and Senate announced Thursday that they will boycott the ObamaCare-created committee responsible for holding down Medicare costs, in a challenge to a controversial element of the health care overhaul. 

The Individual Payment Advisory Board, or IPAB, has been described as a "death panel" by some of its fiercest critics. Though that epithet is not often used anymore to describe the panel, Republicans still say it would hurt seniors by forcing doctors to stop seeing patients. 

House Speaker John Boehner and Senate Republican Leader Mitch McConnell, in a letter Thursday to President Obama, said they would refuse to recommend any nominees to the committee, reiterating that they think it should be repealed entirely. 

They revived concerns that the panel would enforce Medicare cuts by reducing payments to providers and/or "eliminating" certain treatments. 

"These reduced payments will force providers to stop seeing Medicare patients, the same way an increased number of doctors have stopped taking Medicaid patients. This will lead to access problems, waiting lists and denied care for seniors," they wrote. 

The 15-member advisory board, known as IPAB, would have the power to force payment cuts on insurers, drug companies and other service providers if Medicare costs rise beyond certain levels. 

The health care law explicitly forbids the board from rationing care, shifting costs to seniors or cutting their benefits. But Boehner, at a news conference Thursday, said the members still "have the authority to deny seniors access to care." 

It's unclear what effect the boycott will have on the panel. The law says the president should consult with Congress on the nominations, but the president is free to make his own appointments. The members of the board, though, are supposed to be from both parties and nominees would be subject to Senate confirmation.