Actors are working under a contract which expired last month
A breakaway group within the Screen Actors Guild (SAG) has launched a campaign to gain control of the powerful Hollywood union.
It blames the organisation's current leaders for the stalemate in contract talks with major American studios.
The group - calling itself Unite for Strength - hopes to gain a majority on the national governing board in elections in September.
It has unveiled 31 candidates, including Chicago Hope star Adam Arkin.
Other contenders include two actors from Grey's Anatomy spin-off Private Practice - Kate Walsh and Amy Brenneman - as well as Doug Savant from Desperate Housewives.
'Concern for future'
They have accused the current leadership of mishandling talks and straining relations with SAG's smaller sister union, the American Federation of Television and Radio Artists (AFTRA).
The challenge to SAG's ruling coalition - a Hollywood-based group known as Membership First - means the stand-off is likely to drag on for another two months.
Membership First, led by SAG President Alan Rosenberg, swept to power in 2005 after pledging to get tougher with the studios in contract negotiations.
But opponents said Rosenberg's confrontational stance toward AFTRA had backfired.
Arkin said: "I'm concerned for future negotiations if we don't change the leadership that has brought us to this point."
SAG representatives did not comment on his remarks.
SAG, which has 120,000 members, wants more money for actors when their work is released on DVD, plus a greater say in the endorsement of products on-air.
Earlier this month AFTRA approved a new prime-time TV contract with studios.
But a similar deal - which would boost the minimum wages of members by 3.5% in the first year of the contract, 3% in the second and 3.5% in the third - was later rejected by SAG.
In the absence of a new contract, SAG is working to the terms of an old deal, which expired on 30 June.
But Hollywood has slipped into a "de facto strike", with major studios halting most of their film production to avoid the possibility of costly labour disruptions.