NEW YORK - The Obama administration extended the sign-up deadline by two days for Obamacare health-insurance policies that take effect in January, as heavy demand delayed some customers' access to the federal website.

Individuals in the 38 states using the federal shopping portal, including Pennsylvania and New Jersey, have until 11:59 p.m. Pacific time Thursday to buy health plans that take effect Jan. 1, Kevin Counihan, who oversees the marketplaces at the Centers for Medicare and Medicaid Services, said Tuesday in an e-mailed statement. The final date for most people to sign up for 2016 policies is Jan. 31.

This sign-up period, the third under President Obama's health-care overhaul, is being closely watched for signs of how the law is faring. While enrollment so far has been smoother than in the first year of the Affordable Care Act's markets, when the federal website crashed, government estimates of how many people will buy coverage fell short of some expectations.

Health and Human Services Secretary Sylvia Mathews Burwell has said the administration expects about 10 million people to enroll in individual marketplace plans by the end of next year, up from a 2015 year-end projection of 9.1 million. Obamacare set up marketplaces to buy coverage and offers some people subsidies to help them afford it.