Illegal workers cost the food industry millions of dollars in fines and lost revenue each year, and although many companies are pushing for reforms to the US immigrant labor system, the verdict suggests that there is still confusion over how new laws should be applied.

The ruling, issued by Florida district court judge Maxine Chesney, forbids the government from sending out "no-match" letters to employers when their workers' social security numbers do not match the Department of Homeland Security's database.

The Bush administration had originally drawn up the "workplace initiative", announced August 9, as part of a renewed attempt at reducing illegal labor use in the US, much of which occurs in the food industry.

However, the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO) argued that some of the citizens whose information doesn't match the database are in fact legal workers.

These legal workers would therefore be wrongly harassed by "no-match" letters, the union argued.

"These letters have significantly impacted low-income workers of Latin American and Asian descent who use compound last names, which may result in inadvertent errors or discrepancies in their records," said the AFL-CIO.

The court ruled in the union's favor, and filed a temporary restraining order against the DHS.

"The court finds that plaintiffs have demonstrated that…members would suffer irreparable harm if the rule is implemented while defendants would suffer significantly less harm from a delay in the implementation of the rule pending consideration of plaintiff's claims," the judge said in giving his decision.

According to the Washington Post, there are errors in the social security records of an estimated 12.7 million native-born US citizens, 250,000 foreign-born citizens and 4.8 million legal immigrants, potentially creating a paralyzing bureaucratic nightmare for workers and social security administrators.

President George Bush has tried to enforce a number of regulatory measures this year, all designed to monitor and eradicate illegal workforces.

Promised reforms include a temporary work permit system, increased fines against employers breaking the law and broader security.

One company that suffered because of illegal labor was poultry processor Smith & Co., which in 2006 had to reduce production after it was the target of immigration raids.

Government officials arrested around 1,300 workers, mainly immigrants from Mexico, which cost the company about $30m in lost production.

According to Bush, the number of illegal workers caught at manufacturing sites has increased dramatically during his term in office. About 4,300 arrests were made in worksite enforcement cases during 2006, more than seven times the arrests in 2002.