New health insurance exchanges being set up by the federal government in more than 30 states under President Barack Obama's 2010 healthcare overhaul could miss an Oct. 1 deadline for open enrollment, a government report said.

The launch of the exchanges, which are expected to provide health coverage for 7 million people in 2014 and 22 million by 2016 as well as to some small businesses, could determine whether Obama's signature domestic policy achievement succeeds.

The report by the nonpartisan Government Accountability Office said key parts of the framework of the exchanges, including those that addressed consumers' eligibility for federal subsidies, management and monitoring of insurance plans and consumer assistance, had not been completed.

The report found that states had not completed many of the tasks assigned for implementation, while U.S. officials have conducted only initial testing of the computerized system that will link the exchanges, states and the federal government.

But much progress had been made in completing major tasks necessary for implementation, including establishment of the regulatory framework, according to the report.

It added that the Department of Health and Human Services is also planning contingencies to deal with problems and found that interim deadlines that have been missed up to this point may not affect implementation.

"Additional missed deadlines closer to the start of enrollment could (affect implementation)," the report concluded.

"Whether these efforts will assure the timely and smooth implementation of the exchanges by October 2013 cannot yet be determined."

Federal officials, led by U.S. Health and Human Services Secretary Kathleen Sebelius, have vowed repeatedly that the federal exchanges set up under the healthcare law, also known as "Obamacare," will be ready on time in states that have chosen not to implement their own marketplaces, often because of political opposition from Republican governors and legislators.

"We are working every day to establish individual and small business marketplaces, where many Americans will have access to quality, affordable coverage for the first time. We have already met key milestones and are on track to open the marketplace on time," HHS spokeswoman Joanne Peters said on Wednesday.