Hard negotiations, which have been going on for days over the board's demands for new work practices, had reached some compromises.
But as yesterday's board meeting stretched into the night, no new deals had been reached with the technical staff and chorus.
And even improved packages reached by the Musicians' Union and Equity, the actors' union, for the orchestra players and dancers have not yet been put to a ballot of those affected.
Roger Bolton, of the union Bectu, said: "Everything is on a knife-edge."
Monday had been the deadline set by the Royal Opera House for all staff to accept the new cost-cutting measures or face the sack. The board has said that it needs to slash costs until extra funding is available.
Although many performances have been cancelled because of the ROH's renovation works at Covent Garden in central London, others have been scheduled for alternative venues, including the Sadler's Wells theatre. These are now under threat because of the dispute.
Bob Wearn, for the Musicians' Union, said yesterday that hard negotiations, including two days of talks, had won promises of no compulsory redundancies for the orchestra and better hours and pay rates than the management's original offer. The orchestra would be cut from 112 members to 97 through natural wastage.
This deal will be put to members in a ballot on Monday. "The players are under no illusion that it would be very different from the current way they work," Mr Wearn said. "But we have got a lot more concessions."
Martin Brown, for Equity, said it had managed to get "substantial improvements" for the dancers in talks earlier yesterday. These included a full working year of 52 weeks instead of 40 weeks, and better pay and overtime arrangements than were first offered.
But he said: "There is some way to go on the chorus. There are substantial areas that are problematic."
Mr Brown said it had never acknowledged the management's imposed deadline of last Monday. But he added: "We don't expect the Opera House board to issue redundancy notices now. We have come a long way."
A Covent Garden spokeswoman said separate negotiations had been going on with Equity, the Musicians' Union and Bectu, but for contracts to be drawn up all three had to reach agreement on new working practices.
The new Covent Garden is due to reopen in December next year. Management say it must cut costs before it can afford to move in.
But if staff refuse to sign the new contracts and the two performing companies - ballet and opera - are disbanded, it is likely they will not be reformed until mid-2000 at the earliest, with Covent Garden not opening until autumn 2000.
t A performance of the Royal Ballet in front of the Prince of Wales at Sadler's Wells theatre on Tuesday night was delayed by 20 minutes as angry dancers held a union meeting over their dispute. The delay to the Frederick Ashton triple bill came as union leaders told them that management were making few concessions.