Story highlights Wall Street Journal reports figure for online enrollment on HealthCare.gov for first five weeks

Obama administration says enrollment figures not yet final, plans to release them this week

Obamacare website beset by serious problems, but officials say it's getting better slowly

Hundreds of thousands have signed up through states but have not yet completed process

It appears fewer than 50,000 people successfully signed up for health coverage through the federally run Obamacare website during the first five weeks of open enrollment, falling well short of expectations for the period, the Wall Street Journal reported on Monday.

The federal online application process has been marked so far by serious technical problems with HealthCare.gov since its October 1 launch.

The website was established as the main source of public information and the primary way for consumers to purchase private insurance online under the Affordable Care Act, President Barack Obama's signature domestic policy achievement.

The Obama administration is scrambling to fix the problems and says website use is improving daily. It hopes to have the site running smoothly for most people by the end of the month.

Some states are running their own enrollment programs for Obamacare and are faring better.

The online enrollment debacle combined with some people losing their health insurance because of Obamacare have energized Republicans, who have hammered the President politically and see the rocky start as a potent campaign issue heading into next year's congressional midterm elections.

Joanne Peters, a spokeswoman for the Health and Human Services Department, declined to discuss enrollment specifics in responding to the Journal report, which cited unnamed sources familiar with the matter.

"We cannot confirm these numbers," Peters said.

"More generally, we have always anticipated that initial enrollment numbers would be low and increase over time, just as was the experience in Massachusetts, where only 0.3 percent, or 123 people paying premiums, enrolled in the first month," she said of a similar program set up in the Bay State.

"And, as we have said, the problems with the website will cause the numbers to be lower than initially anticipated," Peters said.

The administration has said it will release official data later this week.

A senior administration official, speaking on the condition of anonymity to CNN, said the numbers reported by the Journal were not official and that final official data for the first month of open enrollment is not ready yet.

The Journal's figure is pegged to "834 transmissions" received by insurance companies to complete enrollments. It reported private health plans had received federal enrollment information for 40,000 to 50,000 users.

Marilyn Tavenner, the official charged with implementing Obamacare as director of the Centers for Medicare and Medicaid Services, told congressional lawmakers last week the administration had hoped to enroll 800,000 on the insurance exchanges by the end of November.

That figure would presumably include both the exchanges run by the federal government and those run independently in 14 states and the District of Columbia.

It is not clear if it also included enrollments for a large expansion of Medicaid meant to provide insurance to more low-income Americans.

A CNN analysis of publicly available data from the states with Obamacare exchanges showed 59,441 people had enrolled as of a week ago.

At least 344,808 people have signed up online for coverage through Obamacare's state-run insurance marketplace but have not yet technically completed the enrollment process.

This figure does not include paper applications or those submitted over the phone.