A civil rights suit that alleges

Wal-Mart

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systematically denied women equal pay and promotions was granted class-action status by a federal judge, lawyers for the plaintiffs said.

U.S. District Court Judge Martin Jenkins ruled that six current and former Wal-Mart employees from California can represent all female employees of Wal-Mart who worked at its U.S. stores anytime since Dec. 26, 1998. Lawyers for the plaintiffs said that class comprises 1.6 million people.

"Plaintiffs present largely uncontested descriptive statistics which show that women working at Wal-Mart stores are paid less than men in every region, that pay disparities exist in most job categories, that the salary gap widens over time, that women take longer to enter management positions, and that the higher one looks in the organization the lower the percentage of women," Jenkins was quoted by the plaintiffs saying.

The class is represented by the Washington firm of Cohen Milstein Hausfeld & Toll.

According to the lawyers, the case is the largest civil rights class action ever certified against a private employer. They said the judge described the case as "historic in nature, dwarfing other employment discrimination cases that came before it."

The plaintiffs say that women earn 5% to 15% less than male counterparts in the same Wal-Mart jobs.

A Wal-Mart spokesman couldn't immediately be reached.

Previously, Bentonville, Ark.-based Wal-Mart argued that the case's class size would make it too awkward to manage. The world's largest retailer by revenue had also apparently argued that hiring and promotion decisions are made on the store level, which would not make sex discrimination a corporate pattern.

The women will be allowed to sue for punitive damages as well as back pay and lost earnings for those who were denied promotions.

Wal-Mart has 10 days to ask the U.S. 9th Circuit Court of Appeals to review the case.

Shares of Wal-Mart were moving down 72 cents, or 1.3%, at $54.21 in Tuesday premarket trading.