Kathleen Sebelius, who resigned as secretary of Health and Human Services (HHS) on Friday, told "Meet the Press" on Sunday that she resigned voluntarily and was not forced to quit, but that she was indeed "flat-out wrong" about the readiness of HealthCare.gov to go live on Oct. 1.

The federal Obamacare site repeatedly crashed and hung up during the first two months of operation, delaying sign-ups for health insurance in 36 states.

"The launch of the website was terribly flawed, terribly difficult," Sebelius said on the NBC show. "Could we have used more time and testing? You bet.

"If I had a magic wand and could go back to mid-September and ask different questions based on what I know now, I would," she added. "I thought I was getting the best information from the best experts, but clearly that didn't go well.

"Clearly, the estimate that it was ready to go Oct. 1 was just flat-out wrong."