Second level teachers are to ballot for industrial action which could result in the closure of schools towards the end of October.
The central executive of the Association of Secondary Teachers in Ireland (ASTI) decided on Saturday to hold a ballot on the issue of pay for newly-qualified teachers.
Simultaneously, it is to ask its 17,000 members to vote on withdrawing from carrying out supervision and substitution duties in schools.
The ballots will be counted on October 14th. If they are carried, the union would have to give notice of one week before any industrial action could take place.
ASTI president Ed Byrne said the union would be recommending to members that they back industrial action.
He said the Government had promised under the former Haddington Road agreement that it would restore payment for supervision and substitution duties in two phases beginning this month but that it had withdrawn from this arrangement.
The Government has said it will not pay the first tranche of the supervision and substitution payments - worth about €800 - as the ASTI had repudiated the most recent public service pay deal, the Lansdowne Road accord.
Speaking after the meeting on Saturday, Mr Byrne said: “It takes ballots a while (to complete). If the Government is serious about not having schools closed, it needs to get back into substantive talks with us and not be lecturing us about a slavish adherence to the Lansdowne Road agreement which our members have rejected in a ballot.”
Mr Byrne said the Lansdowne Road agreement was “only a piece of paper”.
He said the ASTI wanted talks on substantive issues such as ending the two-tier pay system and bringing the remuneration of recently-qualified teachers up to the level of those in place before 2012.
He said there had to be equal pay for equal work.
He also said productivity concessions such as the additional 33 annual unpaid hours which teachers originally agreed as part of the 2010 Croke Park public service deal were put in place during a financial emergency and were not supposed to last forever.
The Government has invoked financial emergency legislation introduced last year to impose a series of penalties on members of the ASTI in recent weeks.
Meanwhile, Minister for Education Richard Bruton has expressed his disappointment at the decision of the ASTI to ballot its members on industrial action.
The Minister said he believed continuing dialogue between his department and the ASTI would be in the best interests of schools, parents, students and teachers, as is evidenced by the recent agreements reached with the INTO and TUI.
The Minister said that "if ASTI suspend their directive to withdraw from the Croke Park hours, then the department would suspend the implementation of measures associated with the repudiation of the Lansdowne Road Agreement".
Mr Bruton said his department "remains available to meet with ASTI to discuss their issues of concern, including issues relating to new entrant pay".
