A gala performance of Dublin Carol - a play commissioned from Conor McPherson, the award-winning author of The Weir, to celebrate the three-year, pounds 26m refurbishment - has been delayed until March. The theatre has sold 5,000 tickets for the whole run.
Contractors confirmed on Friday that they would be unable to meet the 7 January opening date for the Royal Court.
Negotiations are being conducted to secure an alternative venue for Dublin Carol. Actors, including the production's star, Brian Cox, were told of the problems on Friday, but continued in rehearsal. All have said that they will be available for a later opening.
Ian Rickson, the Court's artistic director, said yesterday: "This is a nuisance but we won't allow the artistic work to be a hostage to building delay."
Mr Rickson insisted the theatre was "very buoyant" in terms of its artistic work, which continued in the West End during refurbishment. The Arts Council last week announced an pounds 800,000, 45 per cent increase in funding for the Court over the next two years in recognition of its excellence in developing new writing.
"The opening show at the National [Theatre] 20 years ago was in rehearsal for seven months because of delays," he said. Coincidentally, Brian Cox was also in that production, of the play Tamburlaine.
The Royal Court, which received nearly pounds 19m of lottery funding for the work, had already delayed the opening once, in October. It was beset by bitter rows last year over a decision to put one of its backer's names up in lights on the renovated building.
The Royal Court's problems follow headaches at the high-profile redevelopment of the Royal Opera House in Covent Garden. It opened on 1 December, as planned, but was immediately forced to cancel one of its productions because of technical problems.
The Royal Court, a 19th century grade II listed theatre, has premiered plays such as John Osborne's Look Back in Anger which have become modern classics. Its renovation has been hampered by the small space the building occupies.
A spokesman for construction managers, Schal, said it was a hugely complex refurbishment involving more than 60 contractors on a congested site.
"We are not interested in assigning blame - everyone is working extremely hard and no stone will be left unturned in our efforts to get the job finished and the theatre open."
Vikki Heywood, the Royal Court's executive director, refused to be drawn on whether the theatre would be seeking compensation, saying it was too early to establish the financial implications of the delay. It is understood that the main problem is with the installation of the electrics.
Ms Heywood said: "People have been working extremely hard to pull this project together and deliver on time."
Negotiations are under way with a number of London theatres to find a temporary home for the Royal Court.
Ticket holders for Dublin Carol will be offered the chance to see it when the Royal Court is finished - now predicted for mid to late February - or at the temporary venue.