NASHVILLE (AP) - Tennesseans on Tuesday began signing up for health insurance under an online marketplace run by the federal government.

"It's a pretty exciting day, we're hearing only good things," said Michele Johnson, executive director of the Tennessee Justice Center. "If you're uninsured, regardless of your politics, you're really excited to have a path to coverage."

Johnson's group had sued to halt emergency rules enacted by the state Department of Commerce and Insurance to require background checks for anyone giving advice on obtaining coverage under the exchange.

A Nashville judge on Monday denied the attempt to immediately block those rules, but found at the hearing that the state's emergency rules wouldn't cover informal advice given through libraries, churches or health centers.

"The state basically narrowed their interpretation of the rules at the hearing and the court told people that they could go forward helping t heir neighbors enroll without fear of penalty," Johnson said. "And that's huge, because there's so many people trying to help make this really complex process manageable for folks."

The state's average premiums in the exchange rank among the cheapest of the 36 states that have deferred to the federal government to run their exchanges.

Republican critics have argued that the insurance available under the exchanges is more expensive than some of the most basic coverage available on the market now.

Advocates have argued that it's difficult to compare the new policies to existing coverage because the federal law requires even low-level plans to meet certain standards that weren't previously in place.

Gov. Bill Haslam opposes President Barack Obama's health care law but has said he's not trying to establish roadblocks to enrollment. The state isn't doing any outreach or marketing for the program other than pointing people to the online marketplace website.

Open enrollment for coverage beginning in the new year runs from Tuesday through March 31.

There are about 982,000 uninsured people in Tennessee. The state estimated before deciding not to participate in the exchange that about 300,000 could participate in the insurance marketplace, though some estimates put that number as high as 600,000.

Officials have also projected that the exchanges will identify nearly 47,000 people who are eligible but not enrolled in TennCare, the state's expanded Medicaid program, through 2014.