Civil rights groups are challenging an overhaul of North Carolina’s election laws that requires government-issued photo IDs at the polls and shortens early voting.

Hours after Republican Gov. Pat McCrory quietly signed the measure into law Monday, the American Civil Liberties Union’s national and North Carolina chapters, along with the Southern Coalition for Social Justice, jointly filed a lawsuit challenging the law. The suit specifically targets provisions that eliminate a week of early voting and same-day registration and prohibit out-of-precinct voting.

Republicans lawmakers who backed the measure said it was necessary to prevent voter fraud, which they say is rampant and undetected in the Tar Heel state. But Democrats and voting rights advocates say their true goal is to suppress voter turnout, especially among traditional Democratic constituencies such as blacks, students, the elderly and the poor.

Dale Ho, director of the ACLU’s Voting Rights Project, called the law a “disaster” that will cut off voting opportunities for hundreds of thousands of North Carolinians.

“It will turn election day into a mess, shoving more voters into even longer lines,” he said. “Florida similarly eliminated a week of early voting before the 2012 election, and we all know how that turned out — voters standing in line for hours, some having to wait until after the president’s acceptance speech to finally vote, and hundreds of thousands giving up in frustration.”

The ACLU, which filed on lawsuit on behalf of several North Carolina advocacy groups, complained the law will disproportionately black voters because more than 70 percent of black voters used early voting during the 2008 and 2012 general elections.

The law was enacted in the wake of a 5-4 Supreme Court decision in June that struck down a key provision in the landmark 1965 Voting Rights Act that required federal oversight of elections in several states, including North Carolina.

The high court’s ruling cleared the way for North Carolina’s Republican leadership to enact voting law changes without prior federal approval.

McCrory said the law, which won’t take effect until the 2016 elections, will institute “common sense” reforms.

“I am proud to sign this legislation into law,” he said. “Common practices like boarding an airplane and purchasing Sudafed require photo ID and we should expect nothing less for the protection of our right to vote.

“While some will try to make this seem to be controversial, the simple reality is that requiring voters to provide a photo ID when they vote is a common sense idea.”

He added that North Carolinians “overwhelming” support the law, citing polls taken in March and April that show more than 70 percent of state voters back the reforms.

But a Public Policy Polling survey conducted over the weekend shows that only 39 percent of state voters support the law, while 50 percent oppose it.

White voters narrowly favor of the law, with 46 percent supporting it and 44 opposed, while only 16 percent of blacks support the reforms, with 72 percent opposed, the survey said.

Seventy-one percent of Republicans support the law, while 72 percent of Democrats oppose it.