WASHINGTON — The Obama administration announced new steps to expand coverage under the federal health care law on Monday, less than a week after the Government Accountability Office, a nonpartisan investigative arm of Congress, found that the federal government and many states were “behind schedule” in setting up marketplaces where Americans are supposed to be able to buy insurance.

The steps — establishing a Web site and a telephone call center to provide information to consumers — are in preparation for what the government anticipates will be a flood of people buying health insurance starting Oct. 1.

Kathleen Sebelius, the secretary of health and human services, said the call center would be in operation 24 hours a day. The phone number is 800-318-2596. The Web site, www.healthcare.gov, provides information promoting the 2010 health care law and describing new insurance options. The Web site and call center currently have only general information about coverage.

Details about the prices and benefits of health insurance plans to be offered by Blue Cross and Blue Shield and companies like Humana and Kaiser Permanente will be available later this summer. Consumers can file online applications starting Oct. 1. Coverage is to begin on Jan. 1, when most Americans will be required to have insurance.