The Post Primary Teachers Association has walked away from the bargaining table with the Ministry of Education over what it says is an unacceptable offer to improve conditions and increase pay.
Bargaining broke down on Tuesday after 13 days of negotiation over three months.
In addition to a 4% pay rise the secondary teachers' union wants laptops for all teachers and classes kept to a maximum of 30 students.
The Ministry of Education says the Government can not afford the generous salary increases of recent years.
It offered teachers a 1.5% pay rise for the first year, and 1% for the year after.
The Ministry says it urges the PPTA to come back to the bargaining table and reach a realistic settlement.
