"Illegal immigrants may not only be receiving this public benefit through the tax code but may also be tempted to come to the U.S. because of it," Johnson said. "This is just plain wrong."

He also noted a 2009 report by the Treasury Department's Inspector General for Tax Administration that said the tax credit appears to create an incentive for illegal aliens to reside and work in the United States.

"It's time to close the loophole in the tax code that allows illegal immigrants to claim the refundable child tax credit," Johnson said. "This simple change can go a long way toward protecting precious taxpayer dollars."