The secondary teachers' union says the last-minute pay offer that averted industrial action this week by its members was not good enough to be ratified.
But the Post Primary Teachers Association (PPTA) says negotiations are continuing.
On Tuesday the union called off its plan to refuse to teach Year 11 students after the Ministry of Education said it had a new offer.
PPTA president Kate Gainsford says she cannot disclose details of the offer, which have been sent to the union's members.
But she says there is a long way to go to reach a ratifiable settlement.
Ms Gainsford says the union has told the ministry it is in no mood for leisurely talks and its plan for industrial action on each day of this school term remains in place.