The Association of Secondary Teachers in Ireland has warned that there will be further industrial action if the incoming government does not address pay inequality by the end of this year.
ASTI General Secretary Kieran Christie was speaking at a small demonstration at the Department of Education and Skills in solidarity with the Teachers Union of Ireland strike, which has closed hundreds of educational establishments around the country.
Mr Christie said so-called new entrant teachers recruited on 10% lower pay from 2011 had suffered losses "running to tens of thousands of euro".
He acknowledged that some measures that have been taken to address the two-tier pay system across the public sector had reduced the gap between teachers recruited before and after 2011.
However, he noted that staff recruited this year continue to be at a 10% pay disadvantage, with further losses due to the failure to reinstate the H Dip allowance.
Mr Christie said: "The new government coming into being must prioritise this or they will have more days like today when industrial action is taking place."
The ASTI is currently balloting its members to renew a mandate for strike action on the issue.
Members suffered penalties under the Financial Emergency Measures in the Public Interest Act (FEMPI) when they went on strike in 2016, though no such penalties were imposed when the Irish Nurses and Midwives Organisation went on strike last year.
The ASTI has lodged a High Court action arguing that the imposition of sanctions on the teachers constituted unequal treatment.
Mr Christie said FEMPI penalties should never have been used and he does not expect them to be applied to the TUI for taking strike action.
He noted that Minister for Education and Skills Joe McHugh had pledged last April at the teachers' conferences that the issue of pay inequality would get consideration, but said members were "aggrieved" and "frustrated" that no concrete proposals had emerged.
Mr Chrstie said this was why the ASTI is balloting members for another mandate to take industrial action if necessary.
ASTI President Deirdre McDonald described the two-tier pay system as "abhorrent" and "morally objectionable", adding that it was having an impact on students because teachers were "voting with their feet", particularly when many could not get a job with full working hours.
She said the ASTI needed a commitment to resolve the issue, not to review it.