The state health exchanges that are central to the U.S. Affordable Care Act are costing the federal government more than twice its initial budget to complete, Bloomberg reported.

President Barack Obama's administration expects to have spent $4.4 billion in fiscal years 2012 and 2013 on grants to states that are building new marketplaces to sell subsidized health insurance, according to budget proposals released for 2014.

A year ago, the administration had anticipated spending about $2 billion. Costs for the state-run exchanges will reach about $5.7 billion, including grants the administration expects to make in 2014.

That doesn't include extra money needed to set up a "federally facilitated exchange" in 34 states that chose not to cooperate with the president's initiative.

When Congress passed the law in 2010, lawmakers envisioned most states would build their own exchanges, and they were told by their own budget accountants that the startup costs would be about $2 billion.