Members of the union representing camera operators, make-up artists and other behind-the-scenes workers on Hollywood films and TV shows have voted to authorise a strike if they cannot reach agreement with producers on a new contract.
The International Alliance of Stage Theatrical Employees, which represents about 60,000 workers, said that 90 per cent of its members cast ballots and more than 98 per cent of the votes returned were in favour of authorising a strike.
The vote does not mean there will be a walk-out, but it strengthens the hand of the union's leaders in their talks with the Alliance of Motion Picture and Television Producers.
“I hope that the studios will see and understand the resolve of our members,” union president Matthew Loeb said. "If they want to avoid a strike, they will return to the bargaining table and make us a reasonable offer."
"Our people have basic human needs like time for meal breaks, adequate sleep and a weekend."
The union is seeking to reduce working hours that can stretch to about 14 hours a day as the demand for TV shows and films has increased, particularly for streaming platforms such as Netflix, Disney+, Apple TV+ and Amazon Video.
It also wants raises for workers on streaming projects, who get paid less than for work on mainstream and cable TV shows under an agreement signed in 2009, when streaming and online media was in its infancy.
The producers' alliance said it was "committed to reaching an agreement that will keep the industry working" but would require both parties showing "a willingness to compromise and to explore new solutions".
The last major strike in Hollywood was by film and TV screenwriters in late 2007 and early 2008. It lasted three months and shut down all scripted shows, forcing TV networks to air re-runs of comedies and dramas.
The association has offered to improve rest periods between projects and to increase wage rates for crew members working on streaming shows, but the rates would still be below mainstream productions.
The union has won the support of powerful Hollywood labour groups representing actors, directors and writers.
Actors Ben Stiller, Danny DeVito, Brie Larson, Seth Rogen and Kevin Bacon are among those who have sent messages supporting its demands.
"They haul sets, equipment, designs, at all hours in all weather," tweeted Law & Order: SVU actress Mariska Hargitay. "They are the first in and last out.
"They’re owed livable wages and hours, and we owe them our unwavering support. Without them, there is no show."