U.S. giant retailer Wal-Mart Stores Inc., following a legal setback in a sex-discrimination suit involving billions of dollars in claims, said it will contest the decision and ask for a larger appeals-court panel to rehear the case, The Wall Street Journal reported on Wednesday.

A three-judge panel of the Ninth Circuit Court of Appeals in San Francisco on Tuesday affirmed class-action status for a suit alleging gender discrimination in pay and promotion.

More than 1.5 million past and present female Wal-Mart employees are included in the suit.

Wal-Mart, the world's largest retailer by revenue, said it would ask a 15-member panel of the Ninth Circuit Court to review the case. The retailer said it would appeal to the U.S. Supreme Court, if needed.

The appeals court rejected Wal-Mart's argument that class-action status shouldn't be allowed because its stores are individually managed and run, saying there was "substantial evidence" of centralized policies.

The suit, filed in 2001 by six female employees, alleges the Bentonville, Ark. retailer systematically paid women with similar qualifications less than men and frequently overlooked women for promotions.

Persuaded by the plaintiffs' statistical data that Wal-Mart paid women workers 5 percent to 15 percent less than men in comparable jobs, a federal district court judge in San Francisco ruled in 2004 that the lawsuit could apply to all women who have worked for Wal-Mart since December 1998.

According to the report, the largest sex-discrimination settlement to date has been a 508 million dollars payment by the federal government to 1,100 women who said they were denies jobs at the Voice of America and the U.S. Information Agency.

A 240 million dollar settlement in 1992 by State Farm Insurance is the biggest corporate gender-bias settlement to date.