WASHINGTON (AP) -- A senior official involved in implementing President Barack Obama's health care plan says the program's sign-up website continues to improve since its stumbling launch more than a month ago, but senators of both parties at a hearing Tuesday expressed deep concern about the troubled start of the overhaul.
The problems with HealthCare.gov, the site where Americans are supposed to be able to buy insurance plans, have given Republicans new lines of attack against the health law, which they unsuccessfully tried to derail last month in a fight that led to a 16-day partial government shutdown.
Marilyn Tavenner, head of the Centers for Medicare and Medicaid Services, told a Senate committee that the website is now able to process nearly 17,000 registrants per hours with almost no errors. She did not say how many individuals have enrolled for health care through the site. The administration has refused to divulge those numbers, and says they will be made available at mid-month.
Adding to the woes is a wave of cancellation notices reaching consumers whose current individual insurance policies don't meet requirements of the 3-year-old law, better known as "Obamacare."
Republican Sen. Lamar Alexander said that runs counter to Obama's promise that if consumers were satisfied with their current plans, they would not have to change it.
"As the president promised, if you like your health care plan, you can keep it, but in fact the plan cancels millions of individual policies," Alexander said.
Alexander also asked if the administration would support legislation introduced in the Senate to allow individuals to retain their existing coverage if they want to. In response, Tavenner said she hadn't read the legislation, and took no position on it.
White House spokesman Jay Carney declined comment on specific legislation to allow Americans in the private market place to retain current coverage.
Obama's presidential legacy will depend heavily on the successful implementation of the Affordable Care Act, which aims to extend health insurance to millions of Americans now lacking it.
Sen. Tom Harkin, the Democrat committee chairman, expressed his party's uneasiness over the troubled start-up.
"I am as upset as anyone with the difficulties that individuals who want to apply for coverage on the federal marketplace have experienced," Harkin said. "And I want to learn today how those problems will be fixed."
While hoping that the administration can deliver its latest promise that the website will be running smoothly for most people by the end of November, Democrats acknowledge there's no clear evidence yet that will happen. The website went down again in the middle of the day Monday for about 90 minutes.
Tavenner was close to the day-to-day work of setting up the enrollment website, handled by experts within her agency and outside contractors. Through the summer, she assured Congress that everything was on track for a reasonably smooth launch of new health insurance markets in all 50 states.
HealthCare.gov was supposed to provide one-stop shopping for people who don't have a health plan on the job. Its target audience is not only uninsured Americans but those who already purchase coverage individually. Middle-class people can sign up for private coverage made more affordable by tax credits that act like a discount on premiums. Lower-income people will be steered to an expanded version of Medicaid in states that agreed to expand that safety net program.
A new study released Tuesday estimates the potential size of the market nationally at 28.6 million people. The nonpartisan Kaiser Family Foundation says three out of five, or more than 17 million people, will be eligible for tax credits. That includes both uninsured people and those switching over from current individual plans.
Earlier, the Congressional Budget Office estimated that 7 million uninsured people would gain coverage through the marketplaces, a statistic the Obama administration adopted as its own enrollment target.