The American Civil Liberties Union and Southern Coalition for Social Justice are suing North Carolina over a new state law that requires voters to show an official photo ID.
The two groups filed a federal lawsuit against the state hours after the bill was signed into law, saying it violates the Voting Rights Act.
Gov. Pat McCrory referred to the law as "common sense" in a YouTube video response to critics.
"They're more interested in divisive politics than ensuring no one's vote is disenfranchised by a fraudulent vote," he said.
McCrory said protecting the integrity of every vote is one of his most important duties and that the law is popular. A majority of North Carolinians support the law.
The ACLU has taken issue with some of the rules included in the new law. Early voting will be cut by a week, and same day registration and out of precinct voting will no longer be options.
The new law won't come into affect until 2016, giving voters three years to get their accepted form of identification.