Industrial action at schools and colleges throughout the State could begin as early as March, according to one of the three teachers' unions.
The Teachers Union of Ireland (TUI) said if the national agreement contained a performance-related system and an existing pay claim was not dealt with, industrial action could begin that early.
Government sources, meanwhile, have reacted negatively to a fresh 30 per cent special pay claim to be lodged by the Association of Secondary Teachers in Ireland (ASTI).
The sources said the Government was highly unlikely to grant anything close to this figure, particularly if the union was not prepared to accept any form of performance-related pay.
The sources said 30 per cent was an extremely high figure, even for an opening position.
The difference over this and the existing TUI and ASTI early settlers pay claim means industrial action now looks certain.
The ASTI is currently drafting a letter asking the Government to deal immediately with the 5 1/2 per cent early settlers claim.
According to ASTI, this claim arises because teachers settled early in the last national pay round and consequently have fallen behind other public sector groups.
The TUI president, Mr Joe Carolan, said this was an issue for his members too. But, he said, the first issue would be what was contained in the national agreement.
He said if it contained a performance-related system the preparations for industrial action would start immediately.
The TUI and ASTI would meet this week and devise a "common strategy" in relation to industrial action and performance-related pay, Mr Carolan added.
The two unions are unlikely to proceed immediately to a strike. Under ASTI guidelines for industrial action a withdrawal from syllabus and course committees would be the first step.
This could be followed by a withdrawal from extra-curricular activities and eventually a withdrawal of labour.
The early settlers issue may be resolved as part of the national pay agreement, but if there is any connection between this and performance-related pay, the ASTI and the TUI will proceed with their industrial relations plan, sources said yesterday.
The veracity of the weekend decision to leave the Irish Congress of Trade Unions (ICTU) took some ASTI members by surprise.
An amendment calling for the union to defer the pullout for three weeks was rejected, even though the idea was accepted by the ASTI president, Ms Bernadine O'Sullivan.