Four former Amazon Prime Now delivery drivers in Orange County, Calif., are suing the company, arguing that they should have been classified as employees instead of independent contractors and thus should have received overtime pay and other protections, such as workers compensation coverage.

The suit, which seeks class-action status, was filed Tuesday in California state court against Amazon, as well as courier service Scoobeez and its parent company ABT Holdings. In the complaint, the drivers say they were hired by Scoobeez and assigned to work exclusively for Amazon’s Prime Now service, which offers one-hour and two-hour delivery to Amazon Prime members in more than a dozen metro areas. The plaintiffs are seeking back wages and other restitution.

“Defendants schedule plaintiffs to work regular shifts, pay them by the hour, and assign packages for plaintiffs to deliver to Amazon Prime Now customers who place orders for one- to two-hour delivery of all manner of consumer goods using the Amazon Prime Now mobile application,” the complaint reads. “Plaintiffs perform their delivery duties wearing a uniform that identifies them to customers as representatives of Amazon Prime Now. Despite these and other clear indicia that plaintiffs are and were defendants’ employees, defendants have classified them as ‘independent contractors’ and, in so doing, have denied them the benefits and protections of California employment law.”

An Amazon representative declined to comment. A person who answered the phone at Scoobeez said the company had no immediate comment.

The suit is just the latest in a brewing legal battle targeting new, so-called on-demand services like Uber that have historically been built on the backs of independent contractors. If Uber were forced to reclassify its drivers in California as employees, it could potentially cost the company hundreds of millions of dollars.

Prime Now is one of several initiatives Amazon has poured resources into in recent years to speed up delivery times from its warehouses to customers’ doors as it seeks to reduce reasons for shoppers to visit brick-and-mortar stores. Amazon uses a variety of courier and messenger company partners in different cities as it looks for ways to control more of the delivery experience. It recently announced a new program called Amazon Flex that would let individuals who don’t work for delivery companies to deliver items for Amazon, too.