Secondary teachers are to man the barricades with planned one-day strikes over Junior Cert changes.
The standing committees of the Association of Secondary Teachers in Ireland (ASTI) and the Teachers Union of Ireland (TUI) have voted to take a day's strike action on December 2.
A further day of strike action is planned for January, 2015.
Both unions - which represent 27,000 second level teachers - said they already have a strong mandate for industrial action following ballots of membership.
Education Minister Jan O'Sullivan, said that the decision of both second-level teaching unions to strike over reforms to the junior cycle was "disappointing and disproportionate."
"It is deeply regrettable that the ASTI and the TUI have decided to embark on a course of action that will disrupt schools and cause serious inconvenience for students and their families," Minsiter O'Sullivan said.
"This decision is at variance with the potential for progress on junior cycle reform that is currently on the table."
"Over recent months I have accepted the genuine concerns that many teachers had about the future of the junior cycle. In putting a new offer on the table this week I have gone as far as I can to address those concerns while still maintaining the integrity of junior cycle reform."
One of the major bones of contention over the changes is the requirement for teachers to assess 40pc of their own students' work for the exam that will replace the Junior Cert.
Taoiseach Enda Kenny said that in the digital era, new challenges for the education system had to be tackled.
"There is no doubt the Junior Certificate needs to be restructured and changed," he said. "I think it is very important for people to understand that we are entering a different phase of world development here.
"The recent Web Summit in Dublin points out the kind of frontiers ahead that are changing. We need to understand that we need to have our young generation really equipped to be able to meet those changes that are coming at us. I regret that this decision has been taken," he added.
However, the ASTI will not move from its position that the Junior Cert must be 100pc externally assessed.
It is prepared to negotiate on other issues - including increasing the amount of assistance it gives students who carry out project work ahead of the final exam.
"We'll be happy to meet the minister but we would be looking for movement from her on the assessment issue," said ASTI President Philip Irwin.
"But it has to be 100pc external assessment. We can't see talks going anywhere on the basis she has offered."
Mr Irwin said members had "gone as far as we can".
However, the Education Minister is adamant that she has gone as far as she can to address teachers' concerns, while still maintaining the integrity of junior cycle reform.