"The president's had the chance year after year to label China a currency manipulator, but he hasn't done so," Romney said in a statement. "And I will label China the currency manipulator they are on the first day."
The Treasury Department has an opportunity each year to label a country a currency manipulator, which then allows Congress to impose trade sanctions to put pressure on that country.
Some economists have said China's currency is as much as 40 percent undervalued, which means its exports are that much cheaper abroad and U.S. products are overpriced in China.
"You might wonder, what in the world has that got to do with jobs here? Let me tell you: When China manipulates their currency by holding down the value of their currency compared to ours, what it does is makes their products in this country artificially cheap," Romney said. "And that then drives American manufacturers and American producers out of business and kills (U.S.) jobs."
In a question and answer session with reporters in Golden, Colo., Carney said Obama's focus "is on ensuring that our businesses and workers are able to compete on a level playing field."
Obama campaign spokeswoman Jen Psaki said Romney had questioned "the actions of the administration and the President to put in place tariffs on Chinese tires," a strategy she said was "very effective."
"And so that raises questions about his (Romney's) own judgment on some of these issues," Psaki said.