With three months to go before HealthCare.gov opens again for business to Americans seeking insurance through Obamacare, congressional investigators and government accountants are sounding the alarm that consumers could “encounter challenges.”

“The agency needs to make an assessment of … whether they are, in fact, on schedule and whether there are risks to the open enrollment period in 2015,” Government Accountability Office official William Woods told a House panel yesterday.

Lawmakers on the Energy and Commerce Subcommittee on Oversight and Investigations had gathered to discuss the findings of GAO’s new report on implementation of the Affordable Care Act, popularly known as Obamacare.

Published Wednesday, the report examines the Centers for Medicare and Medicaid Services’ management of Obamacare contracts. The agency, part of the Department of Health and Human Services, oversees Obamacare and the associated website HealthCare.gov.

One of the main questions the GAO and lawmakers had for CMS was whether HealthCare.gov would be ready for consumers for the second open enrollment period, which begins in November and ends in February. During that time, consumers will be able to purchase health insurance through the federal exchange for coverage beginning next year.

The GAO report calls on CMS to analyze potential risks before new signups begin:

CMS needs a mitigation plan to address these issues. Unless CMS improves contract management and adheres to a structured governance process, significant risks remain that upcoming open enrollment periods could encounter challenges.

Woods is GAO’s director of acquisition and sourcing management. Rep. Morgan Griffith, R-Va., questioned him on HealthCare.gov’s readiness, asking whether consumers were going to experience problems like those that occurred last October:  site crashes, long wait times, bugs in the system.

Although Woods told lawmakers that in his view risks remain, he noted that CMS said it intended to analyze and mitigate any issues.

Subcommittee members also expressed concern about the ballooning costs of a contract awarded to Accenture, the technology firm tapped to fix HealthCare.gov.

After the online insurance exchange rolled out to system failures and malfunctions last fall, CMS fired CGI Federal, the Canadian company that built it. In January, the agency awarded a one-year, no-bid contract to Accenture to repair the website and improve its functionality.

So far, the Washington, D.C.-based firm has received $175 million from the federal government for its work on HealthCare.gov — nearly double the $91 million price tag on the original contract.

And Woods said the bill likely will continue to rise, based on GAO’s review of  taxpayers’ dollars paid to Accenture several months ago.

“The costs on that contract are almost certainly higher than before,” the GAO official said.

CMS rebutted by arguing that the rising charges resulted from reassessed tasks. The total cost of HealthCare.gov and related systems currently is close to $1 billion.

Following the hearing, Republican oversight leaders — Sens. Orrin Hatch of Utah, Chuck Grassley of Iowa, and Tom Coburn of  Oklahoma, and Reps. Dave Camp and Fred Upton, both of Michigan — sent a letter to CMS Administrator Marilyn Tavenner asking questions about HealthCare.gov contracts. They wrote:

Americans deserve a government that is held accountable, and that accountability should extend to the companies that work for the federal government.

The lawmakers also asked why the Accenture contract increased in cost and what the agency’s estimate is for the final bill.

The Energy and Commerce Committee has held roughly a dozen hearings on implementation of the Affordable Care Act and the effects of the health care law. The GAO report lays out specific CMS management issues that could spell trouble for the next open enrollment period.

Americans generally were in favor of the law when Congress passed it in 2010. However, tracking polls by the Kaiser Family Foundation found that support fell to new lows after HealthCare.gov’s rocky launch last year.

More of those surveyed say they favor Obamacare — 37 percent — now than in October. Still, 53 percent — the highest since Congress passed the law — have an unfavorable opinion.