About 30,000 primary school teachers will be going on strike around the country next Thursday.
The New Zealand Educational Institute says primary school and kindergarten teachers and principals rejected a second offer from the Ministry of Education to settle their collective agreements.
NZEI president Mark Potter said union members want the government to increase staffing and funding to schools and kindergartens and improve current pay offers to attract and retain people.
The current offers from the government did little to address serious issues around funding and understaffing, ratios and sick leave, he said.
"Strike action is the last thing we want to do, but members want to send a message to the government about how serious we are about needing change," Potter said in a statement.
Cost of living rises were a factor, but "the bigger picture is that if we are to retain and attract quality educators we must improve work conditions in the sector", he said.
"We all want the best for our students but without changes to the system we can't give it to them. This affects tamariki, because teacher's working conditions are children's learning conditions."
In a statement put out by the NZEI, one Canterbury primary school teacher said they voted to strike because the offer did not address class sizes and learning support, a Tāneatua primary school principal said currently primary school children were resourced at 30 percent less than their secondary counterparts, while a Nelson kindergarten teacher said they were striking because there was not enough sick leave.
Secondary school teachers are also striking next week, which will mean up to 50,000 teachers will be taking industrial action.
The Ministry of Education said in a statement it has sought to resume bargaining urgently "to avoid disruption to our learners, their families, employers and communities".
"We have been working through PPTA's priorities with them, however, there are still some outstanding issues and we have now approached the Employment Relations Authority to instigate facilitated bargaining urgently. We hope the PPTA has the same urgency."
It said the offer rejected by NZEI members provided a "significant increase".