Primary teachers and principals have warned they might take strike action in 2018 to fight for more pay and changes to their workload.
The union representing them say that teachers are at "breaking point" and are "burning out" while trying to do their jobs.
"Teachers and principals are fed up with seeing children miss out on the education they deserve and we're tired of trying to hold the system together when it's broken," New Zealand Education Institute (NZEI) union president Lynda Stuart said.
Ms Stuart said the union is "Signalling to whatever Government is formed that people are very serious, really worried about attracting and retaining teachers in the profession."
She said children are missing out as teachers are struggling with too much administration and testing, finding support for children with additional needs, and overcrowded classrooms.
"The work/life balance is totally out of kilter. They're not getting the support they need to deal with the complex needs of children."
Ms Stuart said teachers are often having to spend their nights and weekends working, instead of having time out with their families.
Members want a "significant pay rise" and NZEI say the teacher supply crisis will only worsen if current workloads and levels of pay are maintained.
"It's time to do what works for children. That means making teaching and learning as good as it can be by putting more staff in every school, paying teachers properly so they can stay in the job, and giving us the opportunity to develop our careers."
NZEI's annual conference is underway in Rotorua, and the union will begin paid meetings to form a claim from early 2018.
It's not just primary teachers and principals who are calling for action. Post Primary Teachers Association executive member Austin Pageau told Newshub the teaching profession is in danger of a "severe crisis".
"It's not just for teaching - it's going to be a very bad thing for the public education system in New Zealand as we know it. We are at risk of losing a great world-class system that the whole world is jealous of."
Mr Pageau said the new Government needs to step up and make teaching a desirable profession again, and give teachers a manageable workload and adequate pay.
"Teachers give a lot of our time and we're happy to do that but the problem is we've got so much paperwork, these things that takes us away from helping the kids."
He said teaching is no longer seen as a profession that provides people with an adequate lifestyle, who are able to buy a house, raise a family and participate in the community. Mr Pageau said this is why the profession is struggling to attract high-skilled graduates, who have student debt.
Education Minister Nikki Kaye has been approached for comment.