SYDNEY, Australia — Taxi drivers in Australia are suing Uber over lost income, just days before the ride-sharing giant’s stock begins trading publicly in the United States.

In a class-action lawsuit filed on Friday, more than 6,000 taxi, limousine and other types of drivers claim that they were hurt financially by Uber’s 2012 arrival in the country, their lawyers said.

The drivers contend that Uber is operating illegally in Australia because it started its business before receiving regulatory approval.

While other ride-hailing companies waited for legislative approval before setting up business, said Rod Barton, a former driver and one of the lead plaintiffs in the suit, “Uber just jumped in, boots and all, ignoring the law and eroding the value of a multibillion-dollar national industry.”