Seattle City Council's eight members voted unanimously Monday to extend collective bargaining rights to drivers for Uber, Lyft and other ride-hailing services. The councilors lauded the new ordinance as a necessary move to protect the labor rights of drivers.

"Do we want to use the law as a shield or do we want to use it as a sward? I say, let's use it as a sward," said councilwoman Lorena Gonzalez prior to the vote.

She compared the situation of on-demand drivers, who are classified as independent contractors, to that of migrant workers such as her parents who immigrated from Mexico. She understands "the importance of having a voice when you are a low-wage worker" dealing with employers making money "literally off your family's back," she said.

Councilwoman Kshama Sawant also compared sharing economy controversies to longstanding labor issues, saying that rebuilding the union movement could help improve the situations of the growing proportion of U.S. workers who are freelancers.

"The so-called sharing economy is nothing new," she said.

Lyft and Uber disagree with the new ordinance, saying the policy may make driving opportunities with the companies less flexible. The companies say that flexibility is a key benefit the companies provide drivers.

"Uber is creating new opportunities for many people to earn a better living on their own time and their own terms. Drivers say that with flexible and independent work with Uber, 50% of them drive fewer than 10 hours a week, 70% have full-time or part-time work outside of Uber and 65% choose to vary the hours they drive 25% week-to-week," Uber said in a statement.

Lyft made a similar statement, adding concerns about privacy.

"Unfortunately, the ordinance passed today threatens the privacy of drivers, imposes substantial costs on passengers and the City, and conflicts with longstanding federal law. We urge the Mayor and full Council to reconsider this legislation and listen to the voices of their constituents who choose to drive with Lyft because of the flexible economic opportunity it offers," wrote Lyft public policy communications manager Chelsea Wilson.

Clarifying the comment on privacy, Wilson provided a memo from director of the city's Department of Executive Administration Fred Podesta to councilmember Mike O'Brien, in which Podesta raised privacy concerns. "The proposal calls for the City to transmit data about drivers collected by a third party to another third party. How will we ensure sensitivity to privacy issues and the potential liability of transmitting this data?" the memo read.

Uber has previously argued that the new ordinance would violate federal antitrust laws by allowing drivers, who are classified as independent contractors and not employees, to conspire in driving up costs of transportation.

"The ordinance is puzzling because I think it's generally believed to be flatly illegal what they're trying to do, and I assume the courts will look at that if it were to be successful," the Associated Press quoted Uber chief adviser David Plouffe as saying during a recent talk in Seattle.

New York University law professor Samuel Estreicher told the Associated Press that antitrust arguments seem the most likely basis for a challenge of the ordinance.

"If the Seattle ordinance survives challenge, we'll see it in a lot of cities," he was quoted as saying.