For those who want coverage effective Jan. 1 under the Affordable Care Act, the sign-up deadline is 11:59 p.m. Monday.
Consumers who have put off selecting policies are expected to jam websites and call centers, trying to beat the deadline.
The administration added 800 staffers
at its call centers, bringing the total to more than 12,000 trained customer reps.
Officials say they believe they will be able to handle the volume and capacity.
For those who sign up no later than Monday, most insurers will make coverage retroactive to Jan. 1
if the first month's premium is paid anywhere from Dec. 31 to Jan. 10.
The period for people seeking individual insurance to enroll continues through March 31.