The federal budget signed by President Obama on Wednesday reauthorized E-Verify through Sept. 30. An amendment to extend it five years didn't make it into the final budget bill. E-Verify is a Web-based service for employers that checks information from I-9 forms against Homeland Security and Social Security Administration databases to verify if a worker is legally eligible to work in the U.S.

Federal contractors will have to use E-Verify beginning May 21, 2009, under an executive order signed by then President Bush in June, according to the Department of Homeland Security.

The Society for Human Resource Management and other organizations have filed a lawsuit to stop the rule, arguing that such a mandate must come from Congress and that it could expose employers to more lawsuits from workers who feel they were discriminated against on the basis of race or national origin.

Opponents of E-Verify have also argued that the databases it uses contain errors and could cause workers with a legal right to work in the U.S. to be denied jobs.

E-Verify is a voluntary program, although some states require employers to use it.