After getting slammed for proposing using a FedEx-like system for tracking immigrants, presidential candidate Gov. Chris Chrisite (R-NJ) defended the idea Sunday on Fox News.

"I don't mean people are packages, so let's not be ridiculous," said Christie in response to criticism of his proposal at a town hall Saturday to bring in FedEx founder Fred Smith to "come work for the government for three months" to "show these people" how to effectively track immigrants.

"You go online and at any moment, FedEx can tell you where that package is," he said Saturday. "Yet we let people come into this country with visas, and the minute they come in, we lose track of them."

Sunday Christie doubled down on his proposal. "This is once again a situation where the private sector laps us in the government with the use of technology," Christie told Fox's Chris Wallace Sunday. "We should bring in the folks from FedEx to use the technology to be able to do it. There's nothing wrong with that."

Christie pointed out in the interview that 40 percent of immigrants with visas stay longer than they are legally allowed.

Christie's currently running near the bottom of the Republican field, RealClearPolitics reporting that his average between 8/9-8/25 in national polls is around 3.5%, or 11th place.