Secretary of Health and Human Services Kathleen Sebelius vowed Wednesday that the administration is ready to implement key pieces of health care reform later this year despite reports to the contrary.

"We recognize this is a huge undertaking," Sebelius said. "If it was easy, it would have been done decades ago. But we are on track, finally, to get it done."

Enrollment in health insurance exchanges begins Oct. 1, creating a marketplace from which millions of uninsured Americans can purchase coverage. It's a critical provision of the Affordable Care Act because the law mandates all Americans buy health insurance.

But a report last week from the Government Accountability Office found that the federal exchanges are behind schedule, and many important tasks remain incomplete.

"Much remains to be accomplished within a relatively short amount of time," the report said.

States had the choice to join a federal insurance exchange or create their own. Twenty-six states will use federal exchanges and seven others will partner with the federal government in devising their exchanges.

The administration has less than 100 days to get ready for enrollment.

"I want to be clear," Sebelius said, "We are ready to go on Oct. 1."

There were no major new announcements from Sebelius on the Affordable Care Act, or from House Minority Leader Nancy Pelosi, D-Calif., who stood by her side. Instead, the two reiterated that the administration is working to inform the public about the looming changes, and without prompting they responded to concerns that Sebelius' agency wasn't ready for the challenge.

Pelosi volunteered a vote of confidence in Sebelius' abilities to get the job done.

"Secretary Sebelius is a great secretary. Her implementation of this is fabulous," Pelosi said. "She knows of what she speaks. She knows it in detail. More important than that, she has a vision for America that has healthcare as a right for every person, not just a privilege for the few."

For her part, Sebelius insisted that reports of insurance rate hikes in states like California were unfounded.

"We've seen very promising news about rates offered in states from Rhode Island to California," she said, "blowing away the myth that somehow we're going to see rates skyrocket."