WASHINGTON — Republicans plan to seek answers from Health and Human Services Secretary Kathleen Sebelius on the Obama administration’s troubled start for its health care website to buy insurance, and are raising concerns about the privacy of information that applicants submit under the new system.

GOP lawmakers said Sunday that the administration will face intense scrutiny this week to be more forthcoming about how many people have actually succeeded in enrolling for coverage in the new insurance markets.

Medicare chief Marilyn Tavenner is scheduled to appear during a House hearing on Tuesday, followed Wednesday by Sebelius before the House Energy and Commerce Committee. The officials will also be grilled on how such technical problems could have gone undetected prior to the Oct. 1 launch of that website, healthcare.gov.

Democrats said the new system needs more time and it can be fixed to provide millions of people with affordable insurance. Kentucky Gov. Steve Beshear, a Democrat, said the system was “working in Kentucky.”

The problems with the rollout have led to calls on Capitol Hill for a delay of penalties for those remaining uninsured.