The ASTI insists it's entering pay talks in good faith, despite preparing a ballot for strike action over pay.
The union, which represents secondary school teachers, says the government needs to offer a significant pay rise to meet the rising cost of living.
The INTO is also planning to ballot its members in the coming weeks, while the TUI is also expected to put a vote to teachers.
ASTI President Miriam Duggan, hopes strike action can be avoided.
"Our standing committee made the decision that we will ballot members, because it takes time to prepare a ballot, so we have to begin preparations.
"However we're hoping that there's a real window of opportunity int he talks coming up in the next few weeks that we won't have to use that ballot.
"But we must be ready in case it's necessary."
