Australian law firm Shine Lawyers has sued ISG Management Pty. Ltd. claiming it misclassified telecommunication workers as independent contractors since 2011.

The Financial Review reported the class action lawsuit could be worth AUD$400 million (US$290 million) and involve more than 4,700 workers. ISGM, now known as Tandem, ranks among Australia’s largest companies.

In a blog post, Tandem said the claims are misconceived and that it will vigorously defend its model.

“Our sub-contractors are free to provide services to others, have the right to delegate work, have the right to refuse to perform work for Tandem and many engage other workers,” according to the company. “We are confident this relationship constitutes that of an independent contractor.”

It also warned subcontractors that the law firm, Shine Lawyers, may not be giving them the full picture of risks involved in this lawsuit.

The lawsuit was filed Nov. 21, and the named plaintiff in the lawsuit is Robert Mutch. A first case management hearing has been set for Dec. 21, according to court records.

Unlike some similar cases, “it’s involving much more highly skilled work and the implications are really considerable — if these workers are found to be employees they’re going to be owed potentially a lot of money,” Andrew Stewart of the University of Adelaide’s law school told the Australian Broadcasting Company. The case could significantly alter the industrial relations landscape, Stewart told the ABC.