Staff at the English National Opera (ENO) have voted unanimously to ballot for strike action.
Sean Doran stepped down as chief executive of ENO last week
Members of broadcasting union Bectu will receive ballot papers this month, with the outcome widely expected to be in favour of industrial action.
Union demands for a 5% pay increase and raised pension contributions were met with a pay offer by ENO of 2.77%.
Last week ENO chief executive and artistic director Sean Doran stepped down after two years in the role.
Staff at the opera company, based in central London, are unhappy about perceived low pay and unsatisfactory working conditions.
Bectu's national official Willy Donaghy said: "ENO's offer is hopelessly inadequate and staff's reaction has been firm in wanting a better deal.
"The last time members were balloted the outcome was 97% in favour of industrial action and we expect the result of this ballot to be similar."
In addition to asking for pension contributions to be raised from £350 to £670 - the standard sum for manager's pensions - ENO staff are also demanding reduced working hours.
Staff claim they are still being asked to work long hours, but are not receiving their full holiday entitlement.