Second-level pupils face the threat of more strike days as they head into the busy summer exam season.
Today's one-day stoppage by the Teachers' Union of Ireland (TUI) has closed about 400 second-level schools, forcing about 200,000 students to stay at home.
It is also causing severe disruption in colleges of further education, institutes of technology and Technological University Dublin (TU Dublin), including cancellation of lectures. Pupils could be hit by more strikes before the school year is out if the row over two-tier pay scales is not sorted.
Teachers are aiming to maximise pressure on the new government to end pay inequality in the profession.
As his members placed pickets at about 1,000 workplaces today, TUI president Seamus Lahart warned there would be no 'honeymoon period' for the next government.
The TUI has a mandate for further stoppages - and the Association of Secondary Teachers Ireland (ASTI) will ballot members next month on industrial action, including strike.
By the time the ASTI ballot - which is certain to support action - is complete, it may be too close to Easter to arrange a stoppage before the break, which raises the prospect of school closures in the weeks leading up to the June exams.
Any disruption to school life from the end of March, whether immediately preceding the Easter holidays or in the weeks afterwards, would cause considerable upset. This is the period when pupils do their orals and practicals for the State exams.
The Irish National Teachers' Organisation (INTO) is keeping faith with a "talks about talks" process that has been going on around the next public sector pay deal, including the issue of two-tier pay for teachers, and has no immediate plans to ballot on action.
The talks have been suspended pending the election, but INTO general secretary John Boyle said they "must deliver pay equality this year or we, along with the other teaching unions, will have no choice but to consider all options up to and including industrial action".
While much progress has been made in bridging the pay gap that opened between established teachers and new entrants, the cohort recruited between 2011 and 2014 continue to carry big potential losses as a result of cuts imposed in the Troika era.
Mr Lahart said "pay discrimination is hugely demoralising for new and recent entrants, who earn significantly less than their colleagues, particularly in the early years of their career".
He said the worst affected were paid 14pc less on appointment and 10pc less over the first 10 years of their career, which, in money terms, amounted to more than €50,000 at a time when they most needed the money. Overall, teacher unions put the total potential career earning losses at about €100,000.
Mr Lahart said they regret any inconvenience caused to students and families, "but a continuation of pay discrimination risks inflicting further damage on the education system".