Napolitano, in a speech at the Atlanta Press Club Saturday, declined to comment on Georgia's Arizona-like immigration bill, HB 87, the Atlanta Journal Constitution reported.
"This is what (President Barack Obama) has said and I've been saying, state by state won't cut it," Napolitano said. "It's got to be a federal reform of immigration laws."
Napolitano said states are taking on immigration issues because of an "underlying frustration that this has not yet been dealt with at the national level, which is really where it should be dealt with so that there is national consistency where immigration is concerned."
Georgia Gov. Nathan Deal has said he will sign into law HB 87, which creates new requirements to ensure workers are eligible to work in the United States. It also gives police the authority to investigate the immigration status of some suspects.
"We are taking action in the only way that we can," said Deal spokesman Brian Robinson.