The Teachers' Union of Ireland is to take strike action on 4 February over "pay discrimination".
The union has 19,000 members in second-level schools, colleges of further and adult education and Institutes of Technology/Technological Universities.
In a statement, TUI President Seamus Lahart said: "We have exhausted every avenue open to us to bring this matter to resolution and have been left with no choice but to take strike action over the ongoing scandal of pay discrimination."
In October, TUI members voted by a margin of 92% to 8% to engage in a campaign of industrial action, up to and including strike action.
The union said in November that it would take strike action in February unless the matter was resolved.
Speaking on RTÉ's News at One, Mr Lahart said his members have "been patient for nine years" over this issue, which he said sees teachers employed after 1 January 2011 earning significantly less than longer-serving colleagues.
Mr Lahart said it is a coincidence that they will be taking action during one of the final days of the general election campaign, but that this day had been decided by members some time ago, and he said Minister for Education Joe McHugh had been made aware.
He said over 1,100 education centres across the sector will be affected.
Mr Lahart said that Minister McHugh was made "well aware" at the most recent TUI conference that if progress was not made that member would take action.
He said the TUI has "exhausted every pathway available within the Public Sector Stability Agreement but that they have reached a dead end."
He said the issue of pay discrimination has to be a priority issue in the programme for government and the minister "making promises to look at it next year or the year after is simply not acceptable to members."
The Department of Education has said that in 2018 the TUI accepted an agreement that was reached between the Government and the public services committee of ICTU in respect of new entrant pay.
In a statement, it said this agreement was benefiting 18,000 teachers and nearly 5,000 SNAs within the education sector and provided for a series of incremental jumps for teachers employed after 2011.
It says the Government gave a commitment to deal with outstanding issues of concern for teachers and that this will happen either in the context of any pay review mechanism agreed by the parties to the Public Service Stability Agreement, or in the context of the next round of pay talks.