Nine illegal immigrants who worked as janitors at Wal-Mart (search) until they were arrested during federal raids last month have sued the company, accusing it of discrimination.

The nine say they were paid lower wages and offered fewer benefit because they are Mexicans, and they accuse Wal-Mart and its cleaning contractors of failing to pay for overtime, withhold taxes or make required workers' compensation contributions.

Their lawsuit, filed Wednesday in Superior Court (search) in Freehold, seeks more than $200,000 in back pay.

The plaintiffs, who now face deportation, were among 250 people arrested in an Oct. 23 federal immigration crackdown at 60 Wal-Mart stores in 21 states. Theirs is the first lawsuit among the immigrants arrested.

According to the lawsuit, Wal-Mart employed cleaning contractors "with full knowledge" that they paid illegal immigrants less than legal workers.

"Wal-Mart must have known about these violations," the immigrant's lawyer, Gilberto Garcia, told The New York Times (search). "If these people are going to work at Wal-Marts, then Wal-Mart and its contractors should abide by the labor laws."

Mona Williams, Wal-Mart vice president of communications, said the company did not know about the alleged labor violations or that the contractors used illegal immigrants. She said Wal-Mart has long insisted that its contractors obey the law.

"Clearly, hungry lawyers are converging on these illegal immigrants as if they were accident victims," Williams said. "We have seen absolutely no evidence showing that Wal-Mart did anything wrong."

She acknowledged that Wal-Mart has received a letter from federal prosecutors warning that it faces a grand jury investigation into illegal immigrants employed at its stores. An employer can face civil and criminal penalties for knowingly hiring illegal immigrants or failing to comply with certain employee record keeping regulations.

The plaintiffs say they worked at least 56 hours a week and were not paid time and a half for overtime, hours worked beyond 40 a week. They say they were paid $350-$500 a week.

Wal-Mart, the world's largest retailer and the largest private employer in the United States, has 1.1 million domestic employees and about 3,500 stores.