Moore said Infosys' visa issues are an increasing concern with her clients, and she outlined specific recommendations for them to take in response. They include asking for documentation about the visa status of Infosys' on-site employees, and having alternative suppliers in the event of "possible disruption," she wrote .

Infosys' chief marketing officer, Paul Gottsegen, disputes Moore's assertion that Infosys clients are worried, saying it "is very inconsistent to what we hear as we speak to clients."

Gottsegen said the company is reaching out to its customers, "and they are assured that they will continue to get full great that they've had from Infosys for years."

Infosys has about 17,000 employees in the U.S. The company didn't provide a breakdown of how many are on visas, but most of them are. Gottsegen said the company is hiring more permanent workers, including 1,200 U.S. workers last year, and many more this year. The company employs about 150,000 worldwide.

Infosys is telling customers that it didn't have a policy to misuse visas, and is denying the allegations made in Palmer's lawsuit.