WASHINGTON (REUTERS) - The Obama administration called on private health insurers on Thursday to make it easier for Americans to obtain coverage and access medical services starting January 1, even if technical troubles or other issues prevent timely enrollment in Obamacare plans.

The administration formally extended its December 15 enrollment deadline for obtaining insurance benefits on January 1 to December 23, and said it would consider further delays if "extraordinary circumstances" prevent consumers from enrolling.

It also set out a special enrollment period for consumers unable to sign up for insurance because of errors with the website HealthCare.gov or other segments of its insurance marketplace technology.

In addition, the administration extended a federal insurance program for people with severe health conditions, and urged insurance companies to provide retroactive coverage beginning January 1 to consumers who sign up for coverage after the first of the year or make their first premium payments sometime in January.

The administration has made major fixes to HealthCare.gov, which provides access to new federal health insurance marketplaces in 36 states, after a disastrous Oct. 1 launch.

However, US officials are still racing to fix and build features on the "back end" of the system that verify enrollment details and process payments to insurers.

Officials said last week that about 10 per cent of applications to the main website are not being accurately transmitted to insurance companies, fueling fears that people will believe they have obtained insurance for the new year, only to discover they are not actually enrolled.