NASHVILLE (AP) - A new law designed to curb illegal voting by noncitizen residents has gone largely unnoticed, overshadowed by Tennessee's new voter identification law.

But the state elections office will soon compare the names of more than 20,000 noncitizens who hold Tennessee driver's licenses with voter registration records. Anyone listed as a noncitizen and registered to vote will be given 30 days to present proof of citizenship or be purged from the rolls.

"As far as potentially taking ineligible voters off the rolls, it's potentially one of the most important things the Legislature did this year," State Elections Coordinator Mark Goins said. "Because of the photo ID law, it just slid under the radar."

The Department of Safety must provide a list of all noncitizens holding Tennessee driver's licenses or certificates to Goins by Jan. 1.

Goins told the Knoxville News Sentinel (http://bit.ly/ogkk uP ) that he is aware of at least two cases of noncitizens voting in Tennessee - one in Houston County and another in Putnam County. But he said that without this cross-checking of the rolls, there is no way to know how pervasive the practice is.

"I hope for four, or five. It could be 10,000," he said. "It's a shot in the dark."

Goins said he expects the cross-check to be completed before the March 6 presidential primary.

Department of Safety spokeswoman Jennifer Donnals said that 19,562 people currently hold temporary licenses, which are issued to foreign nationals legally present in the U.S.

Another 1,043 noncitizens, some of whom might be illegal immigrants, hold certificates for driving that are still valid although the state no longer issues them. All of those certificates will expire in 2012.

The legislation, which passed in May, was inspired by a similar check in Colorado in which the secretary of state found that thousands of people w ho had obtained driver's licenses with a green card were registered to vote. Although some of them may have become citizens before registering, Colorado Secretary of State Scott Gessler has said his office is "nearly certain" that 106 noncitizens there have registered to vote since August 2006.