UPDATE 1-US court won't reconsider Wal-Mart sex bias case

(Adds details from court opinion, background)

LOS ANGELES, Dec 11 (Reuters) - A U.S. appeals court on Tuesday allowed the biggest sexual discrimination case in U.S. history, against Wal-Mart Stores Inc. (WMT.N), to remain a class-action lawsuit but did leave open the option for an appeal.

The 9th U.S. Court of Appeals said it would not reconsider its decision affirming class certification to the case, rejecting Wal-Mart's request for a rehearing on the matter before the full court. A three-judge panel ruled in a split decision in February that more than 1 million women could join a suit charging bias in pay and promotions.

The recent opinion, which included a revision of the court's Feb. 6 ruling that affirmed a San Francisco federal court's finding, allows the parties to file new petitions for rehearing.

An attorney for Wal-Mart had no immediate comment. The company said in February that it would appeal the class certification to the U.S. Supreme Court, if necessary. Attorneys for Betty Dukes, the longtime Wal-Mart employee who brought the lawsuit in San Francisco, could not be reached for comment.

The plaintiffs estimate they could win billions of dollars in lost pay and damages and that as many as 2 million women who have worked for Wal-Mart in its U.S. stores since 1998 could join the suit.

(Reporting by Gina Keating, editing by Mark Porter)

((gina.keating@reuters.com; +1 213 955 6776; Reuters Messaging; gina.keating.reuters.com@reuters.net)) Keywords: LAWSUIT WALMART/

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