The Teachers’ Union of Ireland and the Association of Secondary Teachers in Ireland have both voted to reject the Lansdowne Road Agreement.
The 15,000 TUI members have joined the 17,000 members of the Association of Secondary Teachers in Ireland in rejecting the LRA, which provides for restoration of some of the public sector pay cuts over the next two years.
92% of TUI members voted to reject the LRA. The turnout was 60%. The ASTI voted to reject the agreement by 74% - though fewer than a third of members voted.
Sources said TUI members felt that the LRA did not address issues of under-staffing and underfunding in education.
In addition there was concern about precarious work and pay for newly-qualified teachers, and about "flex" hours for members in third=level education.
The TUI executive will meet on Friday to decide its next move.
The TUI has already stated that it will not necessarily be bound by the overall acceptance of the LRA by a majority of public sector unions.
The two teaching unions account for around 32,000 of the 298,000 workers in the public service - around 11% of Government employees.
New legislation will allow the Government to withhold increments and refuse to restore supervision and substitution payments to any union that repudiates a collective agreement.
However, it is not yet clear what would constitute repudiation, and what steps the two unions intend to take.
Earlier the ASTI warned that it will "react" if the Government takes any precipitous action following its members' rejection of the LRA.
ASTI General Secretary Pat King acknowledged that the 31% turnout was disappointing, but said the 74% rejection was a clear indication of the frustration of teachers.
He said teachers believed there was very little on offer in the agreement, particularly for the 30% who were in part-time, precarious employment, on lower pay scales, and in an inferior pension scheme.
The ASTI leadership meets tomorrow and Friday to decide its next move - including whether to be bound by the majority vote in favour of the agreement by other public sector unions.
The executive will also consider the new Financial Emergency Measures in the Public Interest (FEMPI) legislation, which permits the Government to withhold increments and the restoration of supervision and substitution payments if a union "repudiates" a collective agreement.
Mr King acknowledged this could mean teachers losing out on payments worth several thousand euro a year for senior members.
The LRA has already been passed by a substantial majority of public service unions, though it was rejected by the Irish Medical Organisation, the Association of Higher Civil and Public Servants, and Unite.
Under ICTU rules, a union rejecting a collective agreement usually agrees to be bound by the majority vote.
