ATLANTA – Critics of a Georgia law requiring voters to present government-issued photo identification asked a federal court yesterday to block its enforcement, arguing that it is unconstitutional.

The motion in U.S. District Court in Rome, Ga., argues that the law adopted this year by legislators disproportionately affects Georgia’s elderly, low-income, and minority voters.

The state is set to file a brief in its defense on Monday, and arguments are scheduled next Wednesday. Unless courts intervene, the law will face its first test in a July 18 state primary.

Georgia already has begun issuing free photo identification cards to those who need them, although only a few dozen had been requested as of yesterday, election officials said.

The state passed a similar voting measure in 2005, but a federal judge blocked it, saying it amounted to an unconstitutional poll tax. Early this year, the Republican-led state Legislature amended it to provide the free IDs and makes them available in every county.

Supporters say the law is needed to prevent election fraud. Critics say there is no evidence of in-person voting fraud in Georgia in at least nine years and that the documents needed to obtain a voter ID are susceptible to fraud themselves.

In addition, the law burdens the poor, elderly, and others who may find it difficult to make a special trip to obtain a card or navigate the requirements of voting absentee, the brief said.

“No amount of tinkering can cure the many flaws in this unconstitutional statute,” said Neil Bradley, associate director of the American Civil Liberties Union Voting Rights Project in Atlanta, which is helping to challenge the law.

A separate challenge filed by a former Democratic governor, Roy Barnes, is scheduled to be heard today in a state court.