WASHINGTON — The federal government’s biggest foray into online commerce has left millions of tech-savvy Americans thoroughly bewildered.

But the insurance industry and others experienced with rolling out new programs say there’s still enough time to fix the glitches with President Barack Obama’s health care law before uninsured people start getting coverage on Jan. 1.

The online enrollment system at healthcare.gov was down again for upgrades in the wee hours today. It made its debut just a week ago and technical experts already have been called in to fix problems several times.

Consumers Monday continued to report delays, as well as problems setting up security questions for their accounts. However, the administration says the site’s crowded electronic “waiting room” is thinning out.

Despite the confusion, the insurance industry has held off public criticism. Alarmed that only a trickle of customers got through initially, insurers now say enrollments are starting to come in and they expect things to improve.

The last major federal health care launch — the Medicare prescription drug program in 2006 — also had big startup problems. Government leaders who oversaw it say things could look very different in a couple of months for Obama’s law if the administration manages to get a grip on the situation.

“There wasn’t enough time for testing, so the dress rehearsal became opening night,” said Michael Leavitt, who was responsible for the Medicare drug plan debut.

“They do have an incentive in the next couple of weeks to get this right,” added Leavitt.