Nearly two weeks after the debut of Covered California, the state's online health insurance marketplace, its website still doesn't offer a way to find out which doctors and hospitals are included in each health plan.

The website tool designed to help shoppers cross-reference tens of thousands of doctors and hundreds of hospitals that belong to the networks of Covered California's 12 insurance providers finally launched last week after earlier promises that it would be available on Oct. 1, the day similar exchanges opened for business nationwide under the new federal health care law.

But when it finally appeared on Tuesday, a hard-to-find online tool was only in place about 48 hours before it was removed from the site because of what exchange officials called "uneven" performance.

Since the new online insurance marketplaces opened 12 days ago, many websites across the country have been plagued by technical glitches. But Covered California's site seems to be less balky and more user-friendly than most.

As a result, the struggle to get the much-needed tool up and running has been an embarrassing issue for exchange officials and led to consumer frustration.

Moreover, once consumers are able to see which medical providers are part of the insurance networks, they might be in for a bit of a surprise: In an effort to keep premiums low, some major insurance companies are limiting the numbers of doctors and hospitals they are offering consumers.

Blue Shield of California confirmed to this newspaper that it will offer only 50 percent of its network doctors and 75 percent of its network hospitals to those who sign up for its exchange plans. Anthem Blue Cross of California will offer 95 percent of its hospitals to exchange customers -- but only 60 percent of its network doctors to consumers, said company spokeswoman Leslie Porras.

After studying the preferences of tens of thousands of its customers, Porras said, "what we learned was that people are willing to make trade-offs in order to have access to affordable health care."

Porras said the lower-cost Blue Cross plans were achieved by "refining our networks to be less broad and ... more focused."

Similarly, Blue Shield spokeswoman Lindy Wagner said the company is confident that its networks will be adequate for its Covered California customers. "We want to keep our exchange product affordable," Wagner said.

The thinning of health care networks is exactly what some critics of the 2010 health law had predicted would happen.

At least one prominent health care consultant believes Covered California is misleading consumers about the kinds of plans they are buying.

Robert Laszewski, who heads Health Policy and Strategy Associates in Virginia, accuses Peter Lee, Covered California's executive director, of consistently downplaying the shortcomings of some of the new plans to Californians.

"He has not been telling them that the cheaper health insurance plans only cover half the doctors and hospitals that are used under employer plans," Laszewski said.

Covered California spokesman Dana Howard disputed the charge that Lee hasn't been forthright. Howard said the exchange is "continually working with health care companies to expand and enhance the number of providers that are within their plans."

The health care law is designed to make affordable insurance available to at least 40 million Americans who now lack health care coverage. The law provides federal subsidies to help pay for insurance but also mandates that most legal U.S. residents purchase a plan by March 31 or pay a minimum $95 penalty. Those who sign up for policies before Dec. 15 will see them take effect on New Year's Day.

Howard said if knowing whether certain physicians or hospitals are in a particular plan is a big part of someone's decision, it's best to hold off from enrolling until the online tool is functioning -- which he said would be sometime this week.

Some insurers' websites, including those of Blue Shield and Health Net, allow consumers to check to see if their doctors and hospitals are on an exchange plan. And Anthem Blue Cross says it's working on a similar tool. Still, Covered California has long advertised that it would offer "one-stop shopping" so that customers would not have to check out several insurance sites.

"We recognize that the consumer experience has not been the best for everyone, and we apologize for that,'' said Larry Hicks, an exchange spokesman.

Covered California customers have reacted with a mixture of exasperation and understanding. By now, many are well aware that the sign-up deadline is still two months away.

When Glenn Stewart, a 63-year-old retired telecom executive from Mountain View, used the website tool last week, it told him there was no hospital within 100 miles of his ZIP code.

But Stewart attributed the snafus to the exchange "just not being ready."

"So I was not agitated about that," he said. "I was expecting it."

Meanwhile, not all providers are reducing the size of all of their plans. Health Net, for example, substantially cut the number of doctors in its HMO plan, which is offered only in Southern California. But spokesman Brad Kieffer said the company's PPO plan in the Bay Area will continue to offer Health Net's full slate of doctors and hospitals.

Kieffer, however, also pointed out that robust network plans are becoming dinosaurs in the industry.

"During the recession, lots of employers found it challenging to continue to offer those full benefit plans,'' he said. "They were demanding that health plans come up with ways to save money."

The cost-cutting move by California's major insurers is putting Kaiser Permanente -- renowned for its comprehensive system of doctors and hospitals -- at a competitive disadvantage in some regions. That's because the health care giant cannot carve out a portion of its system and exclude it for a particular group of people in order to lower premiums, said Kaiser spokesman Marc Brown.

The reduction of health providers in some of Covered California's insurance plans worries some medical professionals.

While it applauds Covered California's mission, the California Medical Association, which represents about 38,000 licensed doctors in the state, says the leaner exchange networks could lead to major problems.

"Our biggest concern is: Will there be enough doctors in the network to see the new patients?" said Lisa Folberg, the CMA's vice president of medical and regulatory policy. "It's something we're carefully watching."

Contact Tracy Seipel at 408-275-0140. Follow her at Twitter.com/taseipel.