The threatened job losses follow the restructuring of the company announced by the artistic director, Adrian Noble, which will see the RSC concentrating its energies on touring, and its original base at Stratford-upon-Avon and pulling out of its London base in the Barbican arts complex.
Current productions, including Julius Caesar and Twelfth Night at Stratford, could be hit but the RSC is more worried about its new shows - Alice, and the Merchant of Venice, which are about to go into rehearsals. Both are due to open in London in October, and transfer to Stratford in November.
The union workers, who in clude stage hands, electricians, and wardrobe staff, could stop both shows in their tracks.
Alice is essential to the company's finances. It is the third of a phenomenally successful series of family musicals, following on from The Secret Garden, still running in a West End transfer, and The Lion, the Witch and the Wardrobe.
Alice, adapted by poet and playwright Adrian Mitchell from the Alice in Wonderland and Through the Looking Glass books, will be directed by an RSC newcomer, Rachel Kavanaugh. The other production under threat, The Mercant of Venice, is also an RSC first for a woman director, Loveday Ingram.
Up to 60 jobs, almost 10% of the workforce, will go at Stratford. Complex negotiations are continuing over the 130 staff at the Barbican, some of whom may be kept on when the Barbican management takes over the theatre.
So far only staff at Stratford-upon-Avon have been balloted, but given their 90% vote in favour of strike. Technicians based at the Barbican are likely to follow their lead when asked to vote in the next few weeks.
The union is due to announce dates for potential industrial action next week.
Assistant general secretary Gerry Morrissey described the ballot as "an overwhelming vote of no confidence in the management.
"We have consistently told the management that their proposals are unacceptable to the staff," he said, adding that they had invited the company to take part in conciliation talks at Acas.
The RSC managing director, Chris Foy, said "Bectu have told us they want a negotiated settlement, and not protracted industrial action".
