The Central Executive Committee of the ASTI has rejected Labour Court recommendations on its pay dispute.
The standing committee of the ASTI had unanimously rejected the new proposals.
The decision was made by the 180 members at Dublin's Burlington Hotel today.
Of the 163 members of the ASTI Central Executive Committee that voted, 151 rejected the government's offer. Ten voted in favour of proposals, with two abstentions.
They are now expected to launch a fresh round of strikes that could affect State examinations.