Updated

Senate Republicans joined their House colleagues in calling on a government watchdog agency to investigate Health and Human Services Secretary Kathleen Sebelius soliciting donations from companies her agency might regulate -- part of an effort to sign up uninsured Americans for ObamaCare.

In recent weeks, Sebelius has asked various charitable foundations, business executives, doctors and churches to donate money to nonprofit organizations that are helping implement President Obama’s controversial health care overhaul.

HHS says it’s perfectly legal and points to a special section within the Public Health Services Act that allows the secretary to solicit financial support for nonprofits doing public health work. But others like Sens. Lamar Alexander, R-Tenn., and Orrin Hatch, R-Utah, argue it’s a conflict of interest and want the Government Accountability Office to look into it.

“The Secretary’s actions show an apparent disregard for constitutional principles and may violate the Antideficiency Act, the prohibition against augmenting congressional appropriations, and executive branch ethics laws,” they wrote in a May 16 letter to GAO Comptroller General Gene Dodaro.

More specifically, GOP leaders want the GAO to provide a detailed report on information including -- but not limited to -- all outside entities Sebelius is involved with, a description of the specific requests made to companies and information about whether the secretary or other HHS staff members received clearance from the designated agency ethics official.

The Republican-led House Energy and Commerce Committee began its probe into the issue by sending a letter Monday to Sebelius and groups she might have contacted.

The letter to Sebelius asks her to provide several pieces of information by May 27 related to the solicitations, including names of those contacted “in this unusual fundraising pitch” as well as phone logs and whether other agency officials were involved.

Committee Chairman Rep. Fred Upton, R-Mich., said: “Despite HHS’ insistence that the secretary did not directly ask for funds, one source said, ‘There was a clear insinuation by the administration that the insurers should give financially to the nonprofits.’ ”

The 11 companies receiving letters include insurance groups Cigna, Kaiser Permanente, United Healthcare and Blue Shield of California.

The Associated Press contributed to this report.