Rep. Marsha Blackburn called Sylvia Mathews Burwell an “interesting choice.”
Sen. Sheldon Whitehouse suggested a "new face" would benefit the healthcare rollout.
Sebelius said she was "flat-out wrong" to believe that HealthCare.gov was ready to go.
The comments signal what is likely to be a more divided confirmation vote for Burwell.
Measure would prevent Medicare Advantage plans from cutting doctors from networks mid-year.
A branch of HHS accused the USDA of "misleading" the public about its research.
President Obama's nominee would have more on her plate than just the healthcare law.
More than 50 percent of voters still disapprove of the law, according to two new polls.
Reid said he hopes the GOP will "work with us" to replace Sebelius quickly.
Obama has selected his OMB director to replace Sebelius.