Secondary school teachers are warning that it remains to be seen if there will be industrial action in their dispute with the Government over the Landsdowne Road agreement.
The ASTI and the TUI unions have rejected the deal to reverse pay and pension cuts.
Both unions will meet separately over the coming days to decide what their next move will be.
General secretary of the ASTI, Pat King, said that while there is no threat of strike at the moment, that may change.
"Certainly, if there is Government action that precipitates something like that, we certainly will respond," he said.
"If there's any attempt by Government to impose or to change the working conditions that we've negotiated, we certainly will respond.
"So that remains to be seen."
The ASTI voted to reject the Lansdowne Road Agreement proposals by 74% to 26%, it was announced yesterday.
Commenting on the result, ASTI president Máire G. Ní Chiarba, said the Agreement does not address the key concerns of teachers.
"Teachers have taken significant cuts in pay in recent years," she said.
"Working conditions have deteriorated through a combination of reduced resources and additional demands on teachers’ time.
"Young teachers have been disproportionately affected due to the introduction of new pay scales and new pension arrangements.
"In addition, part-time teachers, who do not earn a full salary, will not benefit from the January 2016 pay increase."