A senior human resources manager at Toshiba Corp has filed a $100 million lawsuit accusing a U.S. unit of the Japanese technology company of gender bias against women in pay and promotions.

The plaintiff, Elaine Cyphers, contends Toshiba America Inc pays women lower salaries and bonuses than men who perform similar work. She also alleges the company steers women into lower-grade positions and favors men in promotions.

Cyphers said this results in an astounding lack of women in leadership positions, despite Toshiba's creation six years ago of a Gender Equality Office. The complaint said only 3.4 percent of Toshiba's 6,273 managers worldwide are women.

The numbers are atrocious, said David Sanford, a partner at Sanford Wittels & Heisler LLP who represents Cyphers, in an interview. We believe the class claims are significant, and will be substantiated in the litigation.

Toshiba spokesman Tom Gallatin said in an email the company generally does not discuss pending litigation.

Cyphers said she has been human resources manager at Toshiba America Nuclear Energy Corp and the highest-ranking U.S. human resources employee at that unit. She said she was paid $90,000 to $91,800 a year between 2008 and 2010, while men in similar jobs at Toshiba were paid about $120,000 annually.

The lawsuit is the latest of many accusing companies of favoring men over women in the workplace. It seeks class-action status on behalf of all current and former Toshiba female employees in the United States. Cyphers said she also filed a complaint with the Equal Employment Opportunity Commission.

Last July, Novartis AG agreed to pay $175 million to settle a class-action lawsuit accusing the Swiss drugmaker of discriminating against 5,600 women sales representatives in pay and promotions.

Sanford was co-lead counsel for the sales representatives.

The U.S. Supreme Court is expected to decide by June whether Wal-Mart Stores Inc must continue to defend against the largest U.S. class-action gender bias lawsuit in history, brought on behalf of as many as 1.5 million current and former female employees.

Cyphers said she had worked in human resources for a quarter century before Toshiba hired her in June 2008 and moved about 110 miles to Falls Church, Virginia, for the job.

She said Toshiba soon promoted a less experienced man to a new position above her and later sought to force her from the company in retaliation for complaints about discrimination.

When Cyphers returned last month from medical leave, a supervisor told her to leave and not to return until further notice, so she promptly collected her belongings and left, the complaint said.

Cyphers now lives in North Carolina and technically remains a Toshiba employee but is on leave, her lawyer said.

The case is Cyphers v. Toshiba America Inc et al, U.S. District Court, Southern District of New York, No. 11-00642.

(Reporting by Jonathan Stempel; editing by Gerald E. McCormick, John Wallace and Andre Grenon)