King joined other Republican critics who took aim at Gingrich's remarks during a foreign policy debate Tuesday among GOP candidates, The Hill reported.
During the debate, Gingrich, a former House speaker, said he would support an immigration policy that allowed illegal immigrants who had lived in the United States for a lengthy period, obeyed the law and paid taxes to become permanent residents.
"I do not believe that the people of the United States are going to take people who've been here for a quarter of a century … [and] separate them from their families and expel them," Gingrich said. "I do believe we should control the border. I do believe we should have very severe penalties."
King, speaking on Iowa Public Television Wednesday, said, "I think that when you give people even a promise that they can stay in the country after they're here illegally you become more of a magnet and it is a form of amnesty and more people will come in counting on that."
Gingrich called his stance a "humane" one.
"I don't see how the party that says it's the party of the family is going to adopt an immigration policy which destroys families that have been here a quarter-century," Gingrich said. "And I'm prepared to take the heat for saying, 'Let's be humane in enforcing the law without giving them citizenship but by finding a way to create legality so that they are not separated from their families.'"