WASHINGTON – Problems with the federal health insurance website have prevented tens of thousands of low-income people from signing up for Medicaid even though they are eligible, federal and state officials say, undermining one of the chief goals of the 2010 health care law.

HealthCare.gov is primarily seen as a place to buy private insurance with federal subsidies, but it is also a gateway to Medicaid, which generally provides more benefits at less cost to consumers.

That door has been closed for the last six weeks, with the federal government unable to transfer its files to state Medicaid programs as it is supposed to do. The delays are affecting people in 36 states that rely on the federal exchange, regardless of whether those states are expanding eligibility for Medicaid as authorized by the health care law.

Obama administration officials once envisioned a seamless application process. Under rules issued last year by Kathleen Sebelius, the secretary of health and human services, an exchange must transfer information to Medicaid “promptly and without undue delay,” using a “secure electronic interface.”

The administration is not meeting its own standards.

Marilyn B. Tavenner, the administrator of the Centers for Medicare and Medicaid Services, who oversaw the creation of the troubled federal website, said she decided in September to delay the Medicaid transfers so technicians could “spend more time concentrating on the application process” and other priorities.

The Obama administration has adopted what it calls a “no wrong door” policy: If a person files an application with the exchange for private insurance but appears to be eligible for Medicaid, the exchange will automatically transfer the full application to the state Medicaid agency.

“We have not seen much progress on the flow of data from the federal marketplace to the state,” said Monica H. Coury, assistant director of the Medicaid program in Arizona.

People going to an exchange do not necessarily know if they are eligible for Medicaid. If the exchange finds them potentially eligible for Medicaid, it may be faster for them to file separate applications with a state Medicaid office than to wait for the federal government to transfer their files to the state.

Gov. Dave Heineman of Nebraska, a Republican, said the delay was “further evidence that Obamacare is not ready for implementation.”

Matt D. Salo, the executive director of the National Association of Medicaid Directors, which represents state officials, said, “This is not a catastrophe, but it sends a confusing message to consumers.”