The Senate Budget Committee's top Republican said a new government report shows that President Obama's healthcare law will add $6.2 trillion to the deficit over the next 75 years.
"The report reveals the dramatic falsehoods that were used to push [the bill] to passage," Sessions said in opening remarks at a Budget Committee hearing.
"The big taxes increases in the bill come nowhere close to covering the bill's spending. … The big-government crowd in Washington manipulated the numbers to get the financial score they wanted, to get their bill passed and to increase their power and influence."
The GAO will release its report later Tuesday, according to Sessions's staff. The senator requested the study from GAO.
Republicans have argued since the law's passage that it will prove a major liability for the federal budget.
The Obama administration, meanwhile, cites estimates from the nonpartisan Congressional Budget Office (CBO) that the law will reduce the deficit.
Repealing the Affordable Care Act would increase deficit spending by $109 billion over 10 years, the CBO wrote in July 2012.
Updated at 3:25 p.m.