The labor-friendly legislation, which tech companies have opposed, would pave the way for gig workers to join unions and organize among themselves. It would allow more workers classified as contractors at companies like Uber and Lyft to gain access to the full range of benefits offered to full-time employees.

"[The PRO Act] clarifies that employers may not force employees to waive their rights to join together in collective or class action litigation," the White House said in a statement endorsing the legislation. "The bill also closes loopholes in Federal labor law by barring employers from misclassifying workers as independent contractors."

The PRO Act passed the House last February and it is up for another vote in the House this week. But it will likely face significant roadblocks in the Senate, where it would need Republican buy-in to pass. The White House in the statement on Monday said it "looks forward to working with the Congress to enact this critical legislation that safeguards workers' rights to organize and bargain collectively."

A coalition of groups and tech companies including Uber, Lyft, Doordash and Taskrabbit has been lobbying aggressively against the bill.