Secondary teachers have set a date for national action if negotiations on pay aren't resolved.
PPTA president Jack Boyle made the announcement as part of his opening address to the annual PPTA annual seminar at Rotorua's Sudima hotel this morning.
"We have been negotiating with Government for a settlement to our collective agreement since August last year and our members are running out of patience," Boyle said.
"We hope to receive a realistic offer from the Government for teachers to consider on 3 April, but if we don't, we will use the day to publicly protest the lack of progress."
The Government has made three offers, which members described as "not touching the sides" of addressing the issues faced by secondary schools.
The union says there is an unprecedented shortage of secondary teachers, leaving classes without specialist teachers, and a drop of 40 per cent in the number of people completing teacher training in recent years.
"Jacinda Ardern's Government knows the situation in secondary schools isn't business as usual" Boyle said.
"Teachers want to be working with students in our classrooms. We don't want to be put in the position where we have to take industrial action."
"If we have no other options we will. We will take action so that our students will have the educational opportunities that they need and deserve, with great, well-trained and well supported teachers to provide those opportunities."