Secondary school teachers have voted for strike action in a move that's expected to close hundreds of schools next month.

In two ballots, members of the ASTI voted around 4:1 in favour of industrial action.

Senior union members will discuss the implications of the ballot tomorrow, but it's expected they'll withdraw from supervision duties, which would affect up to 400 schools.

ASTI vice-president Ger Curtin says there are two issues on the table - and full industrial action cannot be ruled out.

Education Minister Richard Bruton has expressed his disappointment;

The Minister has repeatedly expressed his belief that dialogue between his Department and ASTI is in the best interests of schools, parents, students and teachers. He has also expressed his willingness to extend the benefits of the recent agreement reached with TUI and INTO on new entrant pay to ASTI members in the context of the union's cooperation with the Lansdowne Road Agreement. This agreement is worth €135,000 to a teacher over their career.

Furthermore, the Minister has also repeatedly offered that if ASTI suspend their directive on withdrawal from the Croke Park Hours while talks are taking place, the Department can in return suspend the implementation of measures associated with the union's repudiation of the Lansdowne Road Agreement.

The issues of concern to ASTI members can only be resolved through dialogue. Following the ballot result today, the Minister hopes that the union can now engage in constructive dialogue with the Department.