WASHINGTON - A senior Democratic senator who served as a lead author of President Barack Obama's healthcare law criticized the administration on Wednesday for failing to alert lawmakers to problems that led to the program's troubled rollout.

Senator Max Baucus, chairman of the US Senate Finance Committee, who worried openly in April that the rollout could become "a train wreck" said he has been disappointed to hear administration officials say they didn't see problems with the federal healthcare website HealthCare.gov coming.

"When we asked for updates on the marketplaces, the responses we got were totally unsatisfactory. We heard multiple times that everything was on track. We now know that was not the case," he told US Health and Human Services Secretary Kathleen Sebelius at an oversight hearing.

But Baucus also sounded a conciliatory note, saying he wanted to avoid assigning blame. "That's in the past," Baucus said. "Now it's time to move forward and figure out how to fix it."

Under the 2010 Patient Protection and Affordable Care Act, also known as Obamacare, it is mandatory for everyone to have health insurance or pay a fine. Republicans oppose the plan on the grounds that it is an unwarranted expansion of the federal government.

The administration is working around-the-clock with the help of outside tech advisers to resolve problems that have plagued HealthCare.gov since it opened on October 1 and reduced an expected flood of new enrollees to a trickle.

Officials have promised to have the website that serves millions of consumers in 36 states working smoothly by the end of November. But continued problems and revelations about people facing health plan cancellations have led to growing anxiety among Democrats. Some, including Baucus, have said the enrollment period may have to be delayed.

But Sebelius told the lawmakers on Wednesday that there would be no further delay to the law's implementation.

"Delay is not an option. We are still at the beginning of a six-month open enrollment that ends at the end of March, and there's plenty of time to sign up for the new plans," she said.

Wednesday's hearing marked Sebelius's second time in the congressional witness hot seat in as many weeks. Last week, before a House of Representative panel, she accepted responsibility for what she acknowledged as a debacle.

She quickly came under fire from Republicans on Wednesday.

Senator Orrin Hatch, the panel's top Republican, blasted Sebelius for earlier assurances that the rollout would go smoothly and a "cavalier" administration attitude that had brought only "broken promises" to millions of uninsured Americans and those with coverage who are now seeing their plans canceled.

"More and more promises made at the time this law was passed are now crumbling under the weight of reality on a daily basis," the Utah Republican said.

"While I am glad that you are accepting responsibility for this disastrous rollout, I would have preferred that you and the rest of the administration were honest with us to begin with."