More than 1000 Northland teachers and principals will strike for at least three hours and may be extended to a full day after the Government turned down their pay demands.
The strike by members of the New Zealand Educational Institute would take place throughout the country from 1.30pm to 4.30pm on August 15.
The decision followed meetings around the country where primary school teachers voted on whether they should accept the pay offer or strike.
The Ministry of Education had offered to increase pay, in the majority of cases, by between 2.2 and 2.6 per cent a year for three years. That offer was a far cry from the 16 per cent increase teachers felt was needed over the same time to retain and recruit staff.
An electronic ballot could be held at the beginning of next term over whether the strike should be extended for the whole day after many NZEI members did not think the half-day strike sent a strong enough message. This is the first time teachers have taken industrial action since 1994.
NZEI has more than 1000 members in Northland out of about 2000 teachers in all primary and intermediate schools.
President of the Te Tai Tokerau Principals' Association Pat Newman said Northland teachers have had enough and would not budge this time around.
"We are fed up at not getting enough help to do our jobs. We need adequate staff in schools like more teacher aides and counsellors and I've been saying that for a long time now.
"There are 1079 children who have high-end needs because of abuse in the past and more kids are coming through, and teachers would not back down from their demands now."
Parents would have to make arrangements to pick up and look after their children from 1.30pm on August 15. Negotiations between the NZEI and the ministry will continue as they try to reach a settlement.
Ministry deputy secretary of early learning and student achievement Ellen MacGregor-Reid said she was disappointed the offer had been rejected while negotiations were ongoing.
"The offer sees trained teachers' base salaries increase between 6.1 to 14.7 per cent over three years which would see the beginner teacher rate increase to $50,280 a year, rising to $55,030 in 2020.
"The offer would also see increases for principals of between 6 and 11 per cent which would see the starting base remuneration of a principal of a school of 50 or fewer students increase to $92,873 in 2020."
Budget 2018 includes $20 million over four years to help increase teacher supply.