One million new visits to Obamacare website Monday: White House

President Barack Obama's chief of staff said on Tuesday that more than 1 million new visitors had checked out the HealthCare.gov website on Monday, the first day after a major overhaul of the troubled site used to shop for health insurance required under new reforms.

White House Chief of Staff Denis McDonough said the website's new queuing system, used in times of high traffic, worked "pretty well," with 13,000 visitors choosing to receive an email to return later on Monday when there was less traffic, and half of that group accepting that invitation.

"No matter what, we're going to see this thing through," said McDonough, who spoke to a forum organized by Georgetown University and law firm Arent Fox.

When it launched on October 1, the website was supposed to make it easy to buy health insurance in 36 states. Other states run their own marketplaces. Consumers needing health insurance by January 1 have until Dec 23 to sign up, while all uninsured Americans are required to have plans by March 31. But the federal website was a flop, frustrating users with errors and slow speeds.

"That's on us. That's on me," McDonough said, echoing apologies that Obama has made for the disaster that has damaged the president's credibility and popularity.

After weeks of around-the-clock fixes, and as the December 23 looms, the government said on the weekend that the website should work well for most Americans.

The White House has signaled that it plans to outline more aggressively the benefits of the healthcare reforms. Obama will kick off the campaign on Tuesday in a speech at 2:30 p.m.

Some of those benefits include ensuring that 129 million Americans with pre-existing medical conditions, including 17 million children, cannot be denied health insurance or charged more for it, McDonough said. McDonough said work will continue to fix the site and that the strong traffic shows there is demand for affordable health insurance.

"I will say that I've worked on many complicated issues - Middle East peace, Iran, and budget deals. And I can tell everybody in this room that reforming the healthcare system is the single most complicated issue I've faced," McDonough said.