Federal and state officials moved Wednesday to strengthen the computer underpinnings of the new online health exchanges, which proved inadequate to handle a flood of consumer inquiries that began as soon as the system opened on Tuesday and continued into the next day.

On the second day of the exchanges’ operation, users were still encountering long waits, malfunctioning Web pages and messages telling them to try again later, particularly in the 34 states where the marketplaces are being managed by the federal government. Most system managers around the country reported that traffic on Wednesday continued to exceed their expectations, though in places it declined somewhat from the peaks of Tuesday.

The federal exchange Web site, healthcare.gov, opened to the public at 8 a.m. Tuesday, and by Wednesday afternoon, it had had 6.1 million unique visitors, the Department of Health and Human Services said — a pace many times as great as the Medicare site had ever seen. “While this overwhelming interest is continuing to cause wait times, there will be continuing improvements in the coming hours and days,” said Joanne Peters, a department spokeswoman.

The rollout laid bare the complexity of the endeavor, which requires state and federal systems, and the work of myriad private contractors, to communicate as a seamless whole. In some cases, officials conceded that they could not be sure which problems were caused by simply not having the computer capacity to handle the initial demand — a shortfall that should correct itself in time — and which might be signs of design flaws or software bugs.