Secondary teachers attached to the ASTI may refuse to work additional hours set out under the Croke Park Agreement as part of a campaign of industrial action.
The standing committee of the teachers union, the ASTI, will meet today to consider its next move after its members rejected the Haddington Road agreement.
Secondary school teachers voted against the deal last week.
General Secretary of the ASTI Pat King said additional working hours, set out under the Croke Park agreement, will be targeted as part of any industrial action.
"They are certainly a target of the government - and they have cut teacher's pay and broken the agreement - it's logical that we would withdraw from the aspects of the agreement that we've committed to."
He said that time includes after-hours meetings and planning sessions.
"We went into that loyally and willingly - and the government changed it - they moved the goalposts," he said.
"Well, we have to respond."