Two teachers unions have backed a motion that could lead to industrial action.
They are protesting a change to the vaccine rollout list, which will now prioritise someone's age instead of their job.
The votes from the INTO and the TUI means the two unions now have support for industrial action up to strikes.
The third major teachers union, the ASTI, is due to vote on a similar motion shortly.
The three have been angered by changes to the vaccine rollout, which will now be based solely on age.
Education Minister Norma Foley yesterday ruled out a change to rollout plan.
But the government now faces possible strikes unless a compromise can be found.