Despite efforts by legal advocates to press the White House on the situation, "there is no indication that infrastructure . . . necessary for conducting informal reviews and fair hearings has even been created, let alone become operational," attorneys for the National Health Law Program were quoted as saying in a December letter to the Centers for Medicare and Medicaid Services, or CMS, which oversees HealthCare.gov.
The Post quoted two knowledgeable people as saying it was unclear when the appeals process would become available.
The system is designed to allow people filing appeals to do so by computer, phone or mail. But only mail is currently available, the newspaper said.
(Read more: States beat US in Obamacare enrollments: Study)
Asked to comment, a CMS spokesman said: "As we work to fully implement the appeals system, CMS is working directly with consumers to address concerns they have raised through this process.
"We have found that the appeals filed are largely related to previous system errors, most of which have since been fixed. We are inviting those consumers back to healthcare.gov where they can reset and successfully finish their applications without needing to complete the appeals process," Aaron Albright said in an email.
(Read more: 'Strong start' for Medicare cost-cutting)
"We are also working to ensure that consumers who wish to continue with their appeal are able to do so," he said.
The health care law, known as Obamacare, is designed to provide health coverage to millions of uninsured people in the United States, but was plagued by a botched rollout in October.
The Obama administration said in late January that enrollment soared in recent weeks to about 3 million.