Secondary school principals are considering industrial action after the groups representing principals abandoned the negotiations.
The Post Primary Teachers' Association and the Secondary Principals' Association said they had walked away from the talks because the Ministry of Education had not yet made an offer.
They said their members would vote on industrial action next week.
"Yesterday was the sixth collective bargaining round that we've had with the Ministry of Education," the president of the Secondary Principals Association, Scott Haines, said.
"Those talks have not been productive, they have not resulted in an offer for us at all and we don't see any value in continuing to negotiate in the manner which we have been thus far. It's clear to us that the ministry are not going to provide an offer that our members will find acceptable."
He said the ministry had been very clear about the financial parameters it would set on an offer and those limits were "not in the ballpark" of what would be acceptable.
The unions had been seeking improvements including a 15 percent pay rise over two years and an increase in annual leave to six weeks.
Mr Haines said the recent settlement for secondary teachers increased the pay of deputy and assistant principals to an extent that reduced the gap between their pay and that of principals. He said that reduced the incentive for people to become principals.
Meanwhile, primary and intermediate school principals began voting today on a possible settlement to their long-running collective agreement negotiations.
The agreement included a clause that would ensure they automatically received any improvements that secondary principals might win in their talks.
The Education Ministry said it wanted to continue bargaining with secondary principals and the unions had agreed to its request for mediation.
[h] Working harder than ever
Mr Haines said a survey by the Council for Educational Research showed secondary principals were working harder than ever.
"A third of our principals are over the age of 60, two-thirds of our principals are working more than 60 hours a week, 40 percent of our principals are working in excess of 66 hours a week. We know that stress levels are up since they were last measured in 2015, and notably extreme stress levels have doubled in the last three years so it's clear to us that there are some significant aspects that need to be looked at," he said.
The secondary principals' pay scale currently runs from about $85,000 a year for schools with 50 students or fewer through to about $160,000 a year for the biggest schools.
They also receive other payments and 60 percent of secondary principals earn more than $150,000.
The chairperson of the Post Primary Teachers Association's Secondary Principals Council, James Morris, said the pay rises recently won by secondary teachers had closed the gap between principals and their senior teachers and managers.
"Deputy principals had an average of about 18.4 percent so what happens is questions start being asked about 'well, why would I step up to the principal's role if it's not really worth my time'," he said.
"We have a significantly aging group of principals with about a third of them over the age of 60, everyone can see the sort of hours that they are working so we want to make sure we are setting up the conditions that makes it sustainable."
Mr Morris acknowledged that if primary and intermediate school principals accepted the deal currently before them, a parity clause in that deal would ensure that secondary principals were arguably fighting for a pay rise not just for themselves but also for primary school principals.
"That is potentially a risk. The pay scales are just one part of the remuneration package, there are other parts where they're not tightly tied together," he said.
Mr Morris said the 400 secondary principals were a relatively small part of the education workforce and it should not be difficult for the government to find a settlement with them.
"However, once you start getting your pay scale tied to others then that certainly adds to the difficulty of getting things tied up."