The new tally brought the cumulative total for October and November to 365,000 people who have selected health plans in new online marketplaces set up in all 50 states and the District of Columbia. Just over 800,000 have been determined eligible for government health coverage including the Medicaid program for the poor.
The data reflects continued technical problems in November with the federal enrollment website, HealthCare.gov, which crashed on its Oct. 1 launch and was subjected to weeks of emergency fixes. The site has appeared to work far more smoothly since the beginning of this month.
A senior administration official said the weak start to the six-month enrollment period has not diminished expectations that President Barack Obama's signature domestic policy will reach a significant proportion of the uninsured in 2014. Before the launch, the nonpartisan Congressional Budget Office had forecast 7 million enrollees for next year.
"We think we're on track and we'll reach the total that we thought," said Mike Hash, health reform director for the U.S. Department of Health and Human Services (HHS).
"We're not exclusively focused on reaching a particular number," he added. "What we're focused on is reaching the millions of people who are really looking for affordable healthcare coverage."
Officials described the figures as "encouraging" news for Obamacare after months of negative publicity over HealthCare.gov and an uproar over coverage cancellations for people whose health plans do not meet the law's new standards that take full effect in January.
The latest report showed more than 44 million visits to federal and state websites or call centers since Oct. 1. It showed 1.9 million people have been determined eligible for coverage but have not yet selected a plan.
The number of people who signed up for coverage through HealthCare.gov quadrupled to more than 100,000 in November from only 27,000 in October, as the administration scrambled to make the site work smoothly for most visitors by a Nov. 30 deadline.
Analysts say December's enrollment numbers will be more telling about whether the sign-up effort will live up to expectations, including a push to enroll some 2.7 million young, healthy adults whose premium payments will help offset the cost of sicker individuals. The December data is not due until next month.
"We know that they were still having problems with the website in a good chunk of November. Reportedly the website issues are getting better and they are seeing large numbers of visitors coming back. But is it actually translating into enrollment" said Matthew Eyles, an executive vice president at the consulting firm Avalere Health.
The 2010 Patient Protection and Affordable Care Act requires most Americans to have at least enrolled in health coverage by the end of next March or pay a penalty. It provides federal subsidies to help lower-income people pay for insurance and establishes a series of new consumer protections and benefit standards.
Millions of Americans who may need benefits to begin on Jan. 1 need to enroll by a Dec. 23 deadline. But whether they will seek plans through an Obamacare marketplace, and whether HealthCare.gov will be able to process higher volumes of visitors, remain open questions.
Administration officials said last week that as many as 10 percent of enrollments processed through HealthCare.gov included errors when they were transmitted to insurance companies.
The government and insurers were due to begin a new effort to reconcile their enrollment data to ensure consumer details were correctly transmitted and eliminate other errors that could prevent people from receiving their benefits come Jan. 1.
The U.S. Centers for Medicare and Medicaid Services (CMS), the HHS agency responsible for the Obamacare marketplaces, was expected to hand over its enrollment data for October, November and early December to insurers so they could begin the cumbersome process of verifying the data, according to insurance industry officials. (Additional reporting by Caroline Humer in New York; Editing by Michele Gershberg and Lisa Shumaker)