The ongoing pay gap between teachers could lead to strike action, according to the Teacher's Union of Ireland.
Their annual congress will today hear about the problems being created by different levels of pay between new teachers who entered the profession before and after 2011.
Despite the government removing two salary scale points, the union says the issue continues to affect recruitment, retention and morale.
General Secretary of the TUI, John MacGabhann, said they would prefer to avoid strike action but it is a possibility.
He said: "We have previously taken industrial action on this. We would prefer that we wouldn't have to do so again, but the TUI will make absolutely sure that we have a mandate for industrial action.
"What we would prefer is to have this resolves on a negotiated basis."
Meanwhile, Fianna Fáil has accused the Education Minister of lacking clarity in his comments on pay equality for teachers.
Minister McHugh attended both the ASTI and INTO conferences yesterday, where he said that the issue was 'unfinished business'.
Fianna Fail education spokesperson Thomas Byrne says he is just buying time.
He said: "This announcement has all the hallmarks simply of an announcement to get the minister through the teacher's conference.
"There's no detail about this, it's extremely vague and the language that the minister is using is slightly different from the language that the Department of Public Expenditure is using
"The minister has made a lot of commitments on a lot of issues at the conference including on the issue of pay, and I think the question is now, when will we see delivery, and that's not clear."