The President of the ASTI says the union would "have to react" to any move to cut teachers pay without agreement.
The ASTI, which represents around 17,000 second-level teachers, is recommending that its members reject new proposals under the Haddington Road pay deal hammered out last week.
Second level teachers voted No in the first ballot of the Haddington Road deal and the result of this vote will not be known until just before Christmas.
Teachers are currently engaged in low-level industrial action which has seen them refuse to take part in meetings outside of school hours.
The Minister for Education Ruairi Quinn has statutory powers available to him if the industrial action worsens, but President of the ASTI Sally Maguire is warning that teachers would have to respond.
"He could cut pay again, he could cut payment for supervision or substitution, which is a big bone of contention with teachers," she said.
She also referred to such powers as "draconian legislation."
However, Don Myers of the National Parents Council said the situation would be resolved if teachers simply accepted the revised Haddington Road deal.
He said parents are becoming increasingly irritated.
"Our big concern here is for those students who would be sitting their exams," he said. "They are losing tuition time."
"And it's costing parents, having to attend to parent teacher meetings during school time – taking time out of work."