The Association of Secondary Teachers Ireland has voted in favour of industrial action which could result in the closure of hundreds of secondary schools over the coming weeks.

The union announced on Thursday afternoon that 78 per cent of members have voted for industrial action in a dispute over penalties imposed on ASTI teachers for repudiating a public service pay deal.

The ballot was based on a turnout of 77 per cent.

The Department of Education warned last week that two out of three - or up to 525 - of the secondary schools in the country faced possible closure if union members voted for industrial action.

The schools affected are mostly ASTI-run voluntary secondary schools, which are typically privately owned and managed by church authorities.

However, a significant number of 90 or so dual-union community and comprehensive schools may also be affected.

Most schools run by the Education and Training Boards (formerly VECs) will not be affected as they are staffed mainly by members of the Teachers’ Union of Ireland.

ASTI president Ed Byrne said: “Today’s ballot results demonstrate the depth of feeling amongst second-level teachers who have endured years of pay cuts and deteriorating terms and conditions. Teachers do not embark on industrial action lightly and strike action is always a very last resort.”

The department’s concern is focused on the withdrawal by ASTI members from supervision and substitution duties, which could lead to widespread disruption or closure of second-level schools on health and safety grounds.

The union is due to issue a directive on Friday following a meeting of its 23-person standing committee, stating when members should withdraw supervision and substitution duties.

This will trigger a race against time for school managers to recruit supervisors to take over the supervision duties of ASTI teachers.

Separately, the ASTI has voted heavily (80 per cent) for industrial action - up to and including strike action - over pay rates for newly qualified teachers. The precise nature of this industrial action has yes to be decided.

Mr Byrne said the scale of the vote “demonstrates the sense of injustice amongst teachers at this treatment of new and recently qualified colleagues”.

He added: “ It shows that teachers at all stages of their careers are prepared to act in a collegiate spirit and stand up for the most vulnerable teachers in their schools.”

On the issue of supervision and substitution, the department wants the ASTI to give notice of at least six or seven weeks of any withdrawal from these duties to allow schools recruit external personnel and for them to be vetted by gardaí.

However, ASTI sources have indicated that they could withdraw supervision duties after schools return from the mid-term break on November 7th. This would give schools about three weeks to prepare.

The department also wants ASTI to confirm that school principals who are members of the union would not be prevented from operating contingency plans to take on and assign such external personnel to carry out supervision and substitution duties.

In addition, it wants assurances that ASTI members will not hinder the activities of any external personnel .

It is understood that if schools close on health and safety grounds due to a withdrawal of supervision and substitution duties, teachers would not be paid as the Department of Education would consider them in breach of their contractual duties.

The withdrawal of duties is not considered strike action. This is because teachers would be available to teach, but not to monitor break times or fill in for teachers who are sick or away on school trips.

Secondary school management bodies have been drawing up contingency plans since the summer to hire hundreds of staff to help prevent schools closing as a result of potential industrial action.

It is understood these supervisors could be paid about €20 an hour and would need to be Garda-vetted in compliance with child-safety legislation. Vetting is understood to take about three weeks, but this could be fast-tracked, according to sources.

However, school management sources say that advertising and recruiting for these posts will take several more weeks.

Under the contingency plan, the boards of management of each schools would be responsible for hiring supervisors, while the Department of Education is understood to be prepared to make funds available.