The Association of Secondary Teachers, Ireland has reiterated and strengthened its opposition to Junior Cycle reform, passing a motion at its annual convention that copper-fastens its stance against teachers assessing their own students for certification purposes.
The Department of Education had responded to earlier concerns around the issue by watering down its proposals around assessment for the new programme.
It reduced the teacher's role to assessing their students classroom performance in tandem with maintaining State certification.
A second teachers union, the TUI, accepted those revised proposals.
This afternoon delegates reiterated concerns around assessing their own students.
Speakers in favour of the motion said they were worried that the limited introduction of classroom assessment in revised proposals was "a slippery slope".
They said students and parents had confidence in the current system that had external assessment.
However, one speaker against the motion warned that the union was opening up "too many war fronts".
Noel Buckley warned delegates to think strategically, saying that there were "only five days a week to go on strike".
However this view was rejected by speakers supporting the motion who said it was the union's job to defend education.
The motion was overwhelmingly carried.
Earlier, ASTI General Secretary Kieran Christie said the union wanted dialogue but it was the Minister for Education who had refused to sit down.
Referring to the union's plans for a series of strikes on the issue in September he warned that the ASTI would not do a deal at any price.
He said if no progress was made the union would take the necessary action to force the issue, and ensure the matter was thrashed out once and for all.
He also warned the incoming government that his union will take "every opportunity" to recover teachers' terms and conditions and will apologise to no one for doing so.
Mr Christie said members' anger over differential pay scales was "entirely justifiable". But he criticised what he called suggestions that the differential pay scales arose because existing public servants had "pulled up the ladders" and abandoned new recruits.
He said such claims were entirely untrue and were being put forward by the same people who had sought to ignite tensions between public and private sector workers a few years ago. He said unions were not part of the talks and government decisions that had led to those cuts.
ASTI votes to end 'Croke Park' hours
ASTI members have voted to stop fulfilling 33 additional hours of work introduced several years ago under a national pay deal.
The so-called "Croke Park" hours oblige teachers to remain in school for 33 additional hours annually.
The time is mostly used for staff meetings.
Delegates at the ASTI conference in Cork described the hours as "demeaning" and "stupid".
One delegate said they had been introduced as a PR stunt to satisfy people who thought teachers had "a handy job".
He said teachers were fed up to the hilt of sitting in meaningless meetings when they could be doing other work such as class preparation instead.
The ASTI has not signed up to the latest pay deal, the Landsdowne Road Agreement.
Haddington Road, to which it is a party, runs out at the end of June.
Speakers argued that when Haddington Road was dead then the 33 Croke Park hours had to die with it.
The convention voted overwhelmingly in favour of ceasing to fulfill the hours from the ending of the Haddington Road agreement in June.