The Irish National Teachers Organisation is to ballot its 36,000 members for industrial action following their rejection of proposals aimed at addressing pay inequality among public servants recruited since 2011.
However, the ballot will not take place until after a month-long period of consultation with members.
General Secretary Sheila Nunan said the union leadership would also be meeting the Department of Education and Skills to discuss the implications of the ballot result.
The INTO rejected the Government’s proposals by a margin of 53% to 47%.
However, the union's rules do not permit industrial action to be sanctioned unless there is a 66% vote in favour.
The dispute centres on a Government decision during the economic crisis to cut pay rates for new entrants by 10%.
As a result, over 60,000 of the State's 300,000 workforce earn less than their pre-2011 colleagues for doing the same work.
Some of those 60,000 people have now been on lower pay for 7 years.
Around 8,000 of the INTO's 40,000 members - a fifth - are affected by pay inequality.
However, all INTO members voted on the new entrant proposals because of the potential consequences if they are rejected.
If the union went on to actively breach the current Public Service Stability Agreement - for example, with industrial action - all INTO members would face delays in payment of increments and pay restoration provided for under the deal.
All three teacher unions - the INTO, the TUI and the ASTI - have noted that while the measures would improve the situation for new entrants, they will not restore full pay equality, as certain allowances which were also abolished for new entrants - some worth over €1,000 per year - will not be restored.
In addition, there will be no retrospection for the losses incurred since 2011.
The ASTI is currently balloting on the proposals. The TUI has accepted them by 53% to 47% but it cautions that it will continue to campaign for full restoration of pay equality.