"New Zealand is facing a significant teacher crisis. We have got to take action now," she said.
"This is a big problem but it is going to take time. It is not going to be a quick fix.
"We have got to make teaching a desirable occupation in New Zealand again," she said.
Greerton Village School principal Anne Mackintosh said the school would be "closed for instruction" tomorrow.
Mackintosh said it was the first time in nearly quarter of a century that teachers had taken industrial action.
"Things are getting so critical now. In my 30 years of running schools, I have never seen it so bad."
Mackintosh said attracting new staff was becoming difficult, particularly finding relievers to cover for teachers when they were sick.
"The number of people wanting to become teachers has just plummeted."
Mackintosh said societal pressures had also changed.
"Teachers are expected to not only teach but be social workers as well."
Proper remuneration was needed to attract more teachers to the profession and retain them in the job, Mackintosh said.
"I fear for the teaching profession in its present state. Enough is enough."
Western Bay of Plenty Principals Association chairman Matthew Skilton said his staff were "gutted" it had got to the stage where teachers had to take strike action.
The principal of Tahatai Coast School said teachers had had enough of increasing workloads without any remuneration.
Ministry of Education deputy secretary of early learning and student achievement Ellen MacGregor-Reid said the ministry was disappointed primary principals and teachers have chosen to strike.
"Teachers and principals do a really important job and reaching an agreement remains a priority for us.
"We are listening to their concerns which is why our offer, alongside a number of announcements that have already been made by the Government, aims to address those concerns."
The ministry has agreed to resume mediation after the strike.
TEACHERS' STRIKE:
When: 10.30am
Where: Coronation Park, along Mount Mainstreet, to Mount Drury
WHAT YOU NEED TO KNOW:
• In June NZEI rejected the ministry's offer to increase pay, in the majority of cases, by between 2.2 and 2.6 per cent for three years.
• Teachers and principals want a 16 per cent pay rise over the two years.
• Members also want to fix the teacher-shortage crisis, more time to teach and lead, and to fix issues related to career development.
• It is the first primary school teachers' strike since 1994.
• The Secretary of Education decides on any pay deductions.
• There will be lots of events, marching and picketing on strike day.
• Budget 2018 provided additional funding including $272 million for learning support, $59m for teacher aides, and $394m for new schools and classrooms.
• As at August 1, 2018, the Government has funded more than 980 teacher education refresher places to remove cost barriers so that teachers can return to teaching faster.
• 139 teachers coming to New Zealand have received the Overseas Relocation Grant to help with their costs as at July 20, and 41 schools have received a Finder's Fee to help with the costs of recruiting these teachers.
• $370m was also set aside in the Budget for 1500 new teaching places by 2021 to meet population growth.
• The number of primary school teachers remaining in the job has increased from 91.8 per cent in 2014 to 93.8 per cent in 2017.
Additional reporting - NZME
