Taoiseach Enda Kenny has fiercely defended the Education Minister amid warnings that teachers threatening industrial action could be in danger of compulsory redundancies.
Mr Kenny said Ruairi Quinn was no "schoolboy bully" following his claims that the Association of Secondary Teachers of Ireland (ASTI) would be given no protection against forced redundancies should they remain outside a much-disputed pay deal.
The Taoiseach urged the union, whose members rejected the Haddington Road Agreement, to reconsider, and insisted there would be no renegotiations.
"I would ask the ASTI to examine the costs to their members of remaining outside the Haddington Road Agreement," Mr Kenny said.
"And far from being some form of schoolboy bully, Minister Quinn has merely pointed out the reality of the situation. This is the Haddington Road Agreement. It will not be renegotiated."
The education minister warned the secondary school teachers that rejecting the agreement means they will lose protection against compulsory redundancies.
He also warned they could face monetary consequences after the Government imposed financial emergency legislation over the summer dealing with public service groups that did not sign up to the agreement.
The ASTI announced on Monday that teachers will refuse to hold planning and policy development meetings and in-service training unless it is during the school day.
The 17,000 members of the union plan to begin the industrial action on October 2.
The Taoiseach urged the ASTI to consider the effects the industrial action will have on its members, as well as pupils and parents.
"This is a decision of the executive board of the ASTI that will see ASTI members withdraw from all meetings outside school hours, which will impact our parents directly; refuse to participate in training for the new junior cycle, which impacts on parents and their children in second level schools; and not take on any management responsibilities without being paid," Mr Kenny said.
"That is the situation that the executive of the ASTI have decided on and that is their decision."
The decision was announced after leaders of the ASTI met to discuss enforcing a ballot of teachers in favour of the action, up to and including a strike.
The union said while teachers are anxious not to disrupt students' education, the vote had been two to one in support of the action.
The ASTI said its members are being directed not to undertake any duties arising from vacant middle management posts unless they receive pensionable pay for the work.
Other teaching unions, including the INTO and the Teachers' Union of Ireland, have supported the Haddington Road agreement which will change pay and working regimes across the public service.