Obama, meanwhile, rejected the GOP attack line, saying the benefits of the health care reforms -- particularly for people previously unable to get health coverage or afford high-cost policies -- were too important to halt progress because of temporary problems such as website difficulties.
"The essence of the law, the health insurance that's available to people, is working just fine," he said. "In some cases, actually, it's exceeding expectations. The prices are lower than expected, and the choice is greater than we expected. But the problem has been that the website that's supposed to make it easy to apply for and purchase the insurance is not working the way it should for everybody. There's no sugarcoating it. The website has been too slow. People are getting stuck during the application process."
The application portion of the website was brought down this weekend for overnight maintenance, as it has been on previous weekends and some weeknights.
An administration official confirmed to CNN that additional government and private technology experts will be brought on to help solve the problems but did not provide any details.
"To ensure that we make swift progress, and that the consumer experience continues to improve, our team has called in additional help to solve some of the more complex technical issues we are encountering," the Health and Human Services department said in a blog post Sunday. "Our team is bringing in some of the best and brightest from both inside and outside government to scrub in with the team and help improve HealthCare.gov."
Two officials said that staffing at call centers has been increased by about 50 percent to help people phoning in, and officials are emphasizing that now, as an alternative, one can enroll over the phone. About 1.2 million calls have been processed from those seeking information.
The administration is still not releasing the numbers on how many people have taken the next step of enrolling: choosing a specific health care plan. The administration has said it will do that only on a monthly basis, so the first tally of enrollment numbers will come in November.
The Congressional Budget Office has said it expects 7 million people to enroll by April 1.
Although the administration tally of applications did not break down how many of the applications came through state-run exchanges, a CNN survey of officials with those exchanges found that at least 257,000 people had signed up for new insurance plans as of Friday afternoon.
Not all of them had made a payment, and not every state responded to the CNN request.
A ConsumerReports.org article last week offered tips for people trying to sign up, but had the following advice for those overwhelmed by the difficulties:
"If all this is too much for you to absorb, follow our previous advice: Stay away from Healthcare.gov for at least another month if you can. Hopefully that will be long enough for its software vendors to clean up the mess they've made."