The Irish National Teachers' Organisation (INTO) executive is to meet next week to discuss holding a ballot on industrial action.
It comes after members rejected a Government pay offer for new entrants to the profession since 2011.
The move was rejected by 53% of the primary school teachers who cast a vote.
The union says the vote shows "the commitment of our membership to secure pay equality", adding that members are standing in solidarity with colleagues who are paid less for doing the same job.
Head of Communications at the INTO, David Geary, insisted that members don't take decisions like these lightly.
He explained: "They're committed to a ballot for industrial action moving forward.
"I think it's fair to say the members who voted for this were aware [...] this was the path we were going down."
Education Minister Joe Mc Hugh says he's disappointed by the decision.
He observed: "I also accept the ballot.
"My messaging to the INTO is that I'd be looking to engage constructively with them."