WASHINGTON, Nov. 23 (Xinhua) -- U.S. President Barack Obama's administrator in Medicare agency, a key player in carrying out the healthcare reform, will resign after his nomination was blocked by Senate Republicans, local media reports quoted officials as saying on Wednesday.

The administrator of the Center for Medicare and Medicaid Services, Don Berwick, will leave his post on Dec. 2, and his deputy Marilyn Tavenner, will take over, according to The Hill, a newspaper specializes in covering the Congress.

Berwick, a Harvard professor known for his work in improving health care system, was nominated in April, 2010, to help carry out the healthcare overhaul. The nomination was blocked in the Senate by Republicans because of political wrangles on Capitol Hill, with 42 GOP senators opposing the nomination.

Berwick was also known to favor European style medicare systems, especially Britain's. The position was a source of Republican opposition to his nomination. He also caused controversy with academic comments such as healthcare being, in definition, redistribution of wealth. Republicans accused him of advocating healthcare rationing, which Berwick denies.