Two Republican congressional leaders have written to Internal Revenue Service Commissioner Doug Shulman demanding information on how the IRS is spending $1 billion in funds the agency received under the health care reform law.

House Ways and Means Committee Chairman Dave Camp, R-Mich., and Oversight Subcommittee Chairman Charles Boustany, R-La., sent a letter to Shulman on Thursday seeking details on how the IRS is using the money it received from the Health Insurance Reform Implementation Fund.

“The Internal Revenue Service has received tens of millions of dollars from this fund to implement parts of the health care overhaul,” they wrote. “As we understand it, this money is to fund IRS health care related activities above and beyond your FY 2012 request of $473.3 million for health care related funding.”

In the letter, Camp and Boustany requested that the IRS provide documents to the committee so that both lawmakers and taxpayers have a better understanding of how the funds are being used. Specifically, they asked the IRS to provide the following information by May 12: all IRS Expenditure Plans related to the HIRIF; the total amounts that the IRS requested from the Department of Health and Human Services for fiscal years 2010 and 2011; the total amounts the IRS received from HHS for fiscal 2010 and 2011; and the total number of full-time employees performing health care overhaul-related work for both fiscal 2010 and 2011. They also want to know whether the IRS plans to request additional HIRIF funds in the future, and if so, the estimated amount and purpose of the request.

In addition, they have also demanded all correspondence, including email, between the IRS and the Office of Management and Budget regarding the Government Accountability Office’s request for any of the above information and all discussions to withhold or delay providing the information.

Congressional Republicans have sought to repeal and defund the health care reform bill, as well as cut funding for the IRS, since winning control of the House this term.