As the national debate over immigration drags on, states are responding with their own legislation directed against illegal aliens.

In the past few years, the number of state bills aimed at regulating immigration increased fivefold, from about 300 in 2005 to 1,562 last year, according to the National Conference on State Legislatures.

Legislatures enacted approximately 240 new laws last year, up from 84 in 2006.

Oklahoma law fines employers who fail to comply with a federal verification system requiring employers to check employee Social Security numbers against a federal database. The state law also makes it a felony to transport or harbor illegal immigrants. A judge has issued an injunction against the state while the law is being contested.

In one of the nation's first tests of state or local laws on immigration, which has been viewed as a federal matter, Hazelton, Pa., barred landlords from renting to illegal immigrants. Businesses could also be denied permits if they hired them. The law was struck down in a court case, but Hazelton is appealing it.

Suffolk County has joined Oklahoma and Arizona in requiring employers to prove that their workers are here legally. In a court challenge, a judge also ruled against the county, which is appealing the ruling.

"There is very much a battle going on at the local level," said Karen Naraski, executive director of the Asian American Justice Center.

The proliferation of state laws concerns Chung-Wha Hong, executive director of the New York Immigration Coalition. "It's impossible for us to keep track of every local ordinance that pops up," he said. "We would rather have a national debate on the national solution for this national problem that we have."

The state laws are seen as a way to prod the federal government into action, thus far not very successfully.