The Obama administration on Sunday reported vast improvement with the HealthCare.gov health-insurance portal that opened with extensive glitches in October, while acknowledging that the site still needs more work.

One sign of ongoing problems came in the form of a blog entry and infographic that Health and Human Services Secretary Kathleen Sebelius published on Huffington Post. Both items provide tips for consumers visiting the site, most notably by encouraging them to use it during off-peak hours — mornings, nights and weekends.

(AP Photo/Jon Elswick) (AP Photo/Jon Elswick)

The online exchange, which helps users shop for insurance to meet the government’s Jan. 1 deadline for virtually all Americans to obtain coverage or incur a penalty, is now functioning at a success rate of about 90 percent, according to administration officials. That’s compared to about 43 percent in October.

MORE: HealthCare.gov meets deadline for fixes, Obama administration says

Sebelius also encouraged consumers still experiencing problems to contact the HealthCare.gov call center for help.

The failed launch of the portal came as an embarrassment for the administration, which had promised that shopping for insurance under the Affordable Care Act, known as Obamacare, would be as easy as buying plane tickets online.

The viability of the health-care legislation largely depends on the administration’s ability to meet its goal of enrolling 7 million uninsured people, particularly those who are relatively young and healthy, in coverage by the end of March.

Failure to do so could force officials to delay some of the key provisions of the law, such as the so-called individual mandate. It would also keep costs high for those who have obtained insurance on the exchanges, since they are likely to be less healthy and therefore more costly.

“We continue to work every day to ensure that every American who wants affordable health insurance has access to these new, quality coverage options — and hope these new tips are helpful to consumers seeking coverage in the days, weeks and months ahead,” Sebelius said in her message.

The HHS infographic reminds prospective buyers that they are entitled to free preventive care and “new essential benefits” under the Affordable Care Act.

On Sunday, Republican lawmakers voiced skepticism about the HealthCare.gov improvements, while their Democratic counterparts expressed optimism.

Rep. Chris Van Hollen (D-Md.) said on NBC’s “Meet The Press” that the administration “hit the big bench marks they set out,” but Rep. Mike Rogers (R-Mich.) raised concerns about information security on the online portal.

Follow Josh Hicks on TwitterFacebook or Google+. Connect by e-mail at  josh.hicks@washpost.comVisit The Federal Eye, The Fed Page and Post Politics for more federal news. E-mail federalworker@washpost.com with news tips and other suggestion.