Marilyn Tavenner Getty Images

More than 5 million people have now selected an Obamacare health insurance plan on a government-run exchange, with just two weeks to go before a March 31 deadline for obtaining such coverage, a top federal official announced Monday. The newly announced tally still leaves the Obama administration about 1 million shy of its revised target of 6 million enrollees by the end of open enrollment in new Affordable Care Act plans that go into effect this year. "With only two weeks to go, we're continuing to work hard to ensure that every American who wants to enroll in affordable coverage by the deadline of March 31 is able to do so," said Marilyn Tavenner, administrator for the federal Centers for Medicare and Medicaid Services, who revealed the milestone in a blog post. (Read more: Eleventh-hour Obamacare rule juggling begins )



"So don't delay—tell your friends and family to sign up today," Tavenner said. Tavenner said that as the deadline gets closer, the federally run Obamacare exchange HealthCare.gov, and the federal call center for assistance shopping for ACA plans has become increasingly busy. "The last several days have been the busiest since December, with the call center taking more than 198,000 calls on Thursday alone—the busiest day since Dec. 23—and more than 130,000 calls over the weekend," she said. "Last week, HealthCare.gov saw more than 4 million visits—and an additional 1 million visits this weekend." Under the Obamacare law, most Americans must, by March 31, obtain some form of health coverage—such as employer-provided insurance; individual market plans, including ones sold on government exchange; Medicare; or Medicaid—or face a tax penalty of as much as 1 percent of total taxable income. The government-run exchanges are offering health plans at a range of prices, often with subsidy assistance available to customers, depending on their income levels. Tavenner's blog post cited the examples of two of the millions of people who have enrolled in Obamacare through either HealthCare.gov, which serves residents of 34 states, or 17 other exchanges run by individual states and the District of Columbia. (Read more: All over the map: States' 'paid' Obamacare rates )

