An IT worker is accusing Tata Consultancy Services (TCS) of discriminating against American workers and favoring "South Asians" in hiring and promotion. His complaint is being backed up, in part, with numbers.

The lawsuit, filed this week in federal court in San Francisco, claims that 95% of the 14,000 people Tata employs in the U.S. are South Asian or mostly Indian. It says this practice has created a "grossly disproportionate workforce."

India-based Tata achieves its "discriminatory goals" in at least three ways, the lawsuit alleges. First, the company hires large numbers of people who hold H-1B visas. From 2011 to 2013, Tata sponsored nearly 21,000 new H-1B visas, all primarily for people from India, according to the lawsuit's count. Second, when Tata hires domestically in the U.S., "such persons are still disproportionately South Asian." And third, Tata disfavors the "relatively few non-South Asians workers that it hires" in placement, promotion and termination decisions.

The lawsuit, which seeks class action status, was filed by Washington law firm Kotchen & Low. It's similar to a lawsuit filed last year against Infosys, also by Kotchen & Low, in federal court in Wisconsin. Both cases have the potential of putting a new light on the operations of the H-1B-dependent offshore outsourcing industry and its use of visa workers. The lawsuit is posted on the site DVG Law Partner, which is also working on this case.

The lawsuit against Tata arrives at a time when a bipartisan group of 10 U.S. senators is seeking an investigation by federal authorities into the displacement of U.S. IT workers by companies that employ H-1B visa holders.

The plaintiff in the Tata case, Steven Heldt, is a former Tata employee and "one of the few non-South Asians to gain employment with Tata." In the lawsuit, Heldt is described as having had a miserable experience during his 20-month employment period at Tata, despite the fact that he holds a bachelor's degree in economics, a master's degree in IT and numerous certifications, and has nearly two decades of experience and a military career that includes "service with distinction" in the U.S. Army's 101st Airborne Division.

Heldt said that during his employment with Tata, he shuffled around to jobs that "often involved only menial responsibilities" and experienced "substantial anti-American sentiment" along the way. The lawsuit contends that one top Tata HR manager instructed recruiters to focus on hiring Indians, and that this official "has expressed his dislike for American workers" and "believes Indians were smarter and better qualified than Americans."

TCS, in response, said that it "is confident that Mr. Heldt's allegations are baseless, and plans to vigorously defend itself against his claims," said Benjamin Trounson, a company spokesman, in a statement.

"TCS is an equal opportunity employer, and as such, bases its employment decisions -- including recruiting, hiring, promotions, retention, and discipline -- on legitimate non-discriminatory business reasons without regards to race, national origin" and other protected characteristics, said Trounson.

In regard to its U.S. hiring, Trounson said that last year alone Tata recruited more than 2,600 U.S. hires, "many of whom are working on technologies and systems that support critical client needs and help to drive America's innovation economy."

Heldt began the process leading up to a lawsuit by filing a complaint under Title VII of the Civil Rights Act of 1964 with the U.S. Equal Opportunity Commission.

Donna Conroy, who heads the tech advocacy group Bright Future Jobs, which highlights discriminatory hiring practices in job ads, said Title VII lawsuits "are unique in their power to force cultural and policy changes in an entire industry."

"Whether [Title VII lawsuits] are won or lost," Conroy said, "the publicity educates readers on proper and improper conduct from HR."

With this lawsuit, Conroy said, "we can start the process of exonerating the American IT workforce who have been relentlessly denigrated in order to hide the tech industry's widespread practice of discriminating against Americans."