The Post Primary Teachers Association says its contract dispute with the Ministry of Education does not just centre around pay rates.
The union, which represents 18,000 secondary school teachers, has walked away from the negotiating table after it rejected pay offer.
The ministry has offered a pay rise of 1.5% in the first year and 1% the year after.
The PPTA wants a 4% increase.
President Kate Gainsford says the Ministry also wants to remove protections around class sizes.
She says the PPTA won't return to the bargaining table until the ministry offers a "more problem solving" approach.
