NZEI lead principal negotiator, Louise Green, said the decision sends a strong message to the Government that it is time to fix this crisis in teaching.

She added that there needs to be better investment in education so that every child can reach their potential, and so that there are enough teachers for every class.

“A clear majority of both member groups voted in favour of a full day, giving a strong endorsement for collective action," Green said.

The full-day strike action replaces the previously planned three-hour strikes.

“We had a clear message from members at the paid union meetings and from feedback and surveys."

“It is 24 years since educators have gone on strike and this is not an action we are taking lightly.”

Lead teacher negotiator Liam Rutherford said public opinion polling showed strong support for more taxpayer dollars being spent on education, including a significant pay increase for educators.

"The National Party's u-turn on teacher pay and new desire for smaller class sizes means there is now no political opposition to addressing the crisis in education," he said.

“The members' decision to take industrial action shows the degree of frustration and conviction among teachers and principals."

Green said it was crucial to attract and retain great teachers.

"Teachers and principals need to have time to teach, time to lead, and be valued for the professionals that we are.

“And all children need to get the support they need to thrive at school," she said.

In June, the Ministry offered a cumulative pay increase of 14.7 per cent to base salaries for graduates with a teaching degree, from $47,980 to $55,030 over three years, along with cumulative increases for later-career teachers, and principals.

However, speaking to EducationHQ at the time of the offer, Rutherford said it did not do enough for later-career teachers.

“We have got a 12-step pay scale and what they have done is, on the early steps that you can come into the profession, they have done four, four-and-a-half per cent a year for three years, but for the rest of the steps they have done approximately two per cent a year for three years on all of the high steps.

“And when you look at it, 86 per cent of teachers are currently working in the steps that will only get the two per cent a year for three years.”

Rutherford added at the time that some of the union’s other claims had been largely ignored, including around workload issues and the request to fund a Special Education Needs Coordinator (SENCO) in every school, to assist children with additional learning needs.

In a statement released today, Deputy Secretary of Early Learning and Student Achievement Ellen MacGregor-Reid said the Ministry was disappointed that primary school principals and teachers had extended their planned strike action to a full day.

 “We value the work principals and teachers do and progressing these negotiations is a priority for us,” she said.

 “We are disappointed the union has decided to take strike action while we are still in the negotiating process.

 “As we announced yesterday we have entered into mediation.

"Both parties wish to explore every possible avenue to reach an agreement.

 “We will continue to negotiate in good faith.”

Any outcome of the mediation will be taken back to NZEI members for their consideration, according to NZEI president, Lynda Stuart.

In a media release National’s education spokesperson, Nikki Kaye, laid the blame for the strike at the foot of the Labour Government.

“This situation is entirely of Labour’s own making.

"It is yet another example of Labour setting unrealistic expectations and failing to meet them.

“In order to prevent the strikes, the Government must go back to negotiations with respect for teachers and their expectations... and at the same time come up with a plan to support working parents on August 15 in the event the strike does go ahead,” she said.

Kaye added that overall teacher pay went up 17 per cent during National’s time in government.

“It’s not just about pay.

"Teachers want better work conditions, and the Government’s offer of 12 minutes extra a week to work individually with kids or plan learning doesn’t cut it.

“We want to see teachers paid more, but we also want to reduce class sizes to improve the conditions for both teachers and children.”