The Education Minister Richard Bruton has expressed his disappointment after the ASTI announced it will ballot its members on industrial action.
The union, which represents more than 18,000 second level teachers, made the decision yesterday at a meeting of its central executive committee .
Members will be balloted on industrial action - up to and including strike action - over new teachers' pay and will also be asked to vote on withdrawal from supervision and substitution duties.
Teachers who entered the profession after 2010 are on different pay scales to colleagues while they may carry out the same duties and responsibilities.
In a separate ballot which relates to measures applied to ASTI members following their rejection of the Lansdowne Road Agreement, members will be asked to vote on withdrawal from supervision and substitution duties.
The results are expected by mid-October.
Minister Richard Bruton (pictured) said it was regrettable that the ASTI seemed "determined to pursue a route of confrontation rather than dialogue".
He said the latter route would be in the best interests of schools, parents, students and teachers.