Supporters of the idea say it is needed to prevent illegal immigrants from securing jobs paid for by the stimulus package -- especially in the construction sector, which is slated to receive US$104 billion if the measure makes it through Congress intact.

But opponents to including the E-Verification component are complaining about the relative unreliability of the system and its inability to stop people from using fraudulent IDs to get work authorization.

The E-Verify system is operated by the 's (DHS) Citizen and Immigration Services, together with the Social Security Administration (SSA). It is a free, voluntary Internet-based employment eligibility verification system that lets employers compare information from an employee's job application with information contained on DHS and SSA databases to determine work eligibility in the U.S.

According to a DHS description of the program, the SSA database against which the matching is done contains more than 425 million records, while the DHS' immigration databases hold more than 60 million records. In most cases, employers get search results in seconds.

Only about 100,000 employers out of more than seven million in the U.S. are currently signed up for the program.