Post-primary schools could be hit with another teachers' strike before Easter in the campaign for an end to pay inequality for newer entrants to the profession.
Leaders of the two unions representing second-level teachers have both said they could not rule out another stoppage within weeks.
The threat of further disruption follows a one-day strike by members of the Teachers' Union of Ireland (TUI), which closed more than half of post-primary schools, forcing about 200,000 pupils to stay at home.
In all, 387 schools were closed and the strike also hit colleges of further education and institutes of technology as 19,000 members stayed out of work.
The dispute has its roots in pay cuts imposed after 2010.
While much of the gap has been closed, TUI president Seamus Lahart said a second- level teacher employed after February 1, 2012, was paid 14pc less on appointment and 10pc less over the first 10 years of their career, amounting to a loss of more than €50,000 at a time when they most needed the money.
Meanwhile, TUI general secretary John MacGabhann said it may engage in further industrial action before Easter.
He said the union would reflect on the effectiveness of yesterday's action - and a political lobbying campaign in which it is involved - before deciding the next step.
Mr MacGabhann also referred to uncertainty on when a new government might be formed, and said that would influence deliberations.
The other second-level teachers' union, the Association of Secondary Teachers Ireland (ASTI), was not directly involved in yesterday's stoppage but did stage a solidarity protest outside the Department of Education.
The ASTI has announced a ballot of its members seeking support for industrial action, including strike, with a result due on March 20, two weeks before schools close for Easter holidays on April 3.
ASTI general secretary Kieran Christie said the prospect of industrial action before Easter could not be ruled out.
The wording on the ballot paper commits the ASTI to take action only in conjunction with one or both of the other teacher unions, the TUI and the primary teachers' union, the Irish National Teachers' Organisation (INTO).
While ASTI support for action seems likely, the tight timeframe between the ballot and Easter holidays, and the need to agree a date with another union, may be a constraint on a pre-Easter stoppage involving its members.
Both the ASTI and TUI will have to consider the impact of any action on the heavy schedule of orals and practicals for the State exams, starting on March 27.
However, with its mandate for action already in place and no obligation to join forces with another union, there is no constraint on TUI being back on the picket lines before the end of March.
The INTO has not yet balloted on action and has no immediate plans to do so, which means after Easter would be earliest it could be involved in a stoppage.
But if schools escape further action before Easter, there may be disruption in the final term.
While the worst effects of yesterday's stoppage were felt mainly in the education and training boards and community and comprehensive schools, where the TUI is the dominant or main union, it also closed 52 schools in the voluntary secondary sector.
John Curtis, general secretary of the Joint Managerial Body, which represents the voluntary secondary sector, said they would be "concerned that there would be any further action, especially as we move towards the orals".