Toshiba Corp.'s U.S. business was hit with a $100 million lawsuit Monday for alleged "systemic, companywide" discrimination against female staff over pay and promotions, a law firm representing one of the plaintiffs said.

The class action employment lawsuit, filed with the U.S. District Court for the Southern District of New York, claims that Toshiba America Nuclear Energy Corp. and its parent, Toshiba America Inc., engage in systemic gender discrimination against their female employees.

The lawsuit was brought by Elaine Cyphers, a human resources manager at Toshiba America Nuclear Energy who joined the company in June 2008. The suit was filed on behalf of a class of female Toshiba employees in the U.S., according to the firm.

It alleged that the defendants pay female employees less than their male counterparts, deny them promotions to better and higher-paying positions, limit their employment opportunities to lower and less-desirable job classifications, and expose them to different treatment as employees.