ASTI members are planning to hold seven days of strike action for equal pay
Minister for Education Richard Bruton has described planned strike action by teachers as an "unreasonable" strategy.
The Association of Secondary Teachers Ireland (ASTI) is to strike on seven days in October, November and December, as well as withdraw from supervision and substitution duties from November 7th.
Union members backed industrial action as part of a dispute over pay for newly-qualified teachers.
But Minister Bruton told Newstalk’s Sunday Show that he thought the move unnecessary.
There are "real benefits being made available to teachers if they come within the approach" adopted by the TUI and INTO, he said.
A deal reached with the two other teachers' unions last month will see their new members receive pay increases worth up to €2,000.
The agreement is aimed at addressing the controversial two-tier pay system for teachers taken on since February 2012.
It does not apply to recent recruits in the ASTI, however, because of their union’s rejection of the Lansdowne Road Agreement.
Minister Bruton told the Sunday Show that the restoration being sought by the ASTI would cost €2.3 billion and require money to be taken from next year's budget.
The Department of Education has invited the ASTI to attend fresh talks next week, he said.
"[The union] has sought to go for industrial action instead of engaging in a meaningful way in making progress in the same way all other public service unions have done."
Minister Bruton also appeared to confirm reports that the department is considering hiring parents as supervisors to keep schools open.
Closures can only be averted if principals assist with department contingency plans, which the ASTI will not allow them to do, he said.
"We still hope to see if local arrangements can be made, but if the principal isn’t cooperating with telling people how they are to be deployed, it would be very difficult."
On the same programme, ASTI chief Ed Byrne dismissed claims that the union was not prepared to negotiate, insisting it had turned up to every talk.
He described the assertion that "Lansdowne Road is the only game in town" as "ridiculous" and "almost childish".
“We’re in there to try talk and solve problems, not be lectured and preached to,” he said.
Mr Byrne added that teachers were reluctant to interrupt the running of schools and remained available for talks without preconditions.
The ASTI is Ireland's largest second-level teachers' union, with 17,500 members teaching in more than 520 schools nationwide.
Its strike action is due to take place on: