The Obama administration says about 1 million new consumers have signed up for 2016 coverage under the president's health care law.

Another 1.8 million current customers have contacted HealthCare.gov to switch plans or renew their coverage after reviewing their options, officials said Wednesday in a weekly update.   

Although premiums are increasing in most states, HealthCare.gov CEO Kevin Counihan says he's optimistic about a strong open enrollment season.   

Tuesday Dec. 15 will be the first big test: It's the deadline for consumers to sign up for subsidized private coverage that takes effect Jan. 1.   

Current customers who take no action will be automatically renewed.

Open enrollment ends Jan. 31, and the administration estimates there are still about 10 million uninsured people eligible. Fines will rise for those who don't get coverage.