Up to 30 secondary schools in Sligo, Leitrim and Donegal will be affected if the ASTI votes to go on strike.
The 18,000 members of the Association of Secondary Teachers Ireland are currently voting on proposals aimed at resolving a series of disputes between the union and the Department of Education.
The union’s executive council recommended that members reject the proposals and a result of the ballot will be known by the end of next week.
There are over 700 ASTI members in the North West.
Neil Curran is the union’s representative and he says any industrial action would affect all schools
