Talks aimed at healing deep divisions within Mr David Trimble's Ulster Unionist Party (UUP) were suspended yesterday after rival factions prepared for another showdown.
With another critical meeting of the party's ruling council expected to take place early next month, senior members decided to call a halt to any further internal discussions.
Sir Reg Empey and Mr Jim Rodgers pulled the plug on talks after learning a requisition order had been given to party officers.
The order requests a meeting of the 900-member council to discuss disciplinary action against three MPs. Unionist Party officers will meet this evening to consider the request.
A UUP source said: "The meeting could come as early as September 8 or 9 but that will be a matter for the party officers to decide. It's certainly going to be a difficult meeting for everyone."
Sir Reg and Mr Rodgers said: "As people are aware, we decided in early July to hold a series of meetings with leading party members with a view to finding a consensus on the way ahead for the party as we approach a possible autumn election.
"We were coming to the end of that process and were at the stage of concluding our meetings and assessing what, if any, recommendations we might make to the party officers when news of the proposed meeting of the UUC reached.
"We are in no doubt that the only way that the Ulster Unionist Party can resolve its difficulties is by members talking and working towards agreement. This was true in July, is true today and will be true after any UUC meeting. There is no other way."
Sir Reg, a former Stormont economy minister, and Mr Rodgers, an honorary secretary of the party, said talks would not take place until either the requisition was dealt with or a council meeting had taken place.
Ulster Unionists have been bitterly divided over British and Irish government plans for implementing the Good Friday agreement.
Rebel MPs Mr Jeffrey Donaldson, the Rev Martin Smyth and Mr David Burnside resigned the party whip at Westminster in June over the UUC's failure to completely reject London and Dublin's joint declaration.
In July, a High Court judge in Belfast ruled attempts by Mr Trimble and his supporters to suspend the three MPs were invalid because they broke party rules. A second bid to discipline the MPs has since been launched.
The disciplinary moves have unnerved several UUP members and created doubts about Mr Trimble's leadership.