There are likely to be serious recriminations at a meeting of the ASTI's central executive council (CEC) tomorrow over its controversial industrial relations campaign, which is currently on hold.
The union's 180-member body meets to decide on future strategy, amid increasing tensions about who is responsible for the failure of its five-month campaign for a 30 per cent pay rise.
The tensions centre on the tactics used during the campaign and whether a different approach is now needed.
There is little agreement on the way forward. Some members want to set up a committee to look at the ASTI's future direction, while others want to enter benchmarking with other teacher unions.
The former ASTI president, Ms Bernadine O'Sullivan, supports getting a rise through an increased "early settlers" claim.
This was a payment awarded to unions which settled early in the last national pay round. Teachers have been awarded 3 per cent under this heading, but some ASTI members are trying to reopen the issue.
There is also anger among many members at the union's performance in the media, and there are likely to be questions about the hiring of a public relations company.
The union meets as the other two teacher unions begin talks with the Department of Education on a new supervision/substitution regime for schools.
The INTO and the TUI are likely to seek at least £30 an hour for supervision/substitution during the talks which begin today.
The ASTI, at its annual conference in Galway, voted not to take part, although there are now internal differences over whether this policy should be reversed. One motion for the CEC is expected to suggest a review of the position, while another proposes holding a ballot on whether the union should join these talks.
One senior member last night said: "It would be crazy for us to be sitting outside these talks while the other teacher unions are inside getting their members a big allowance".
The union needs to decide shortly on whether to join these talks because, with summer holidays approaching, the CEC may not get another chance to consider the issue before September.
School managers and the Department of Education have called on the union to join, but have also said that non-teachers may be used to provide supervision/substitution instead.
The union has to ballot on future industrial action, likely to involve supervision withdrawal and non-co-operation with the Department of Education, although it is not clear when this will take place.