Rotorua primary school principals and teachers say the Government is not listening and children will suffer.
Their comments come after the New Zealand Educational Institute (NZEI) revealed earlier in the week that members had voted via electronic ballot to reject the Ministry of Education's most recent offer to settle the collective agreements.
But the Ministry of Education told the Rotorua Daily Post it was taking the teachers' concerns seriously.
The union has called paid union meetings in the second week of next term.
If no progress is made by then, it is proposing members vote on taking partial strike action by working to rule from May 15 until a nationwide strike on May 29.
The work to rule would mean working only from 8am to 5pm, Monday to Friday.
They have already held two one-day strikes in August and November last year.
Classroom release time, resources, teacher aides and salaries were the key issues Rotorua educators felt the Government ignored in the latest offer.
Lynmore Primary School principal Lorraine Taylor said the Government had no idea about teacher workloads.
"The offer is so small it's almost invisible. They offered three minutes a day [of classroom release], it's almost insulting.
"Teachers are having to work from 7am to 10pm and at least one weekend just to stay on top of the workload. It's a serious health problem."
Taylor said teachers did not want to strike and many could not afford to take time off.
Otonga Road Primary School principal Linda Woon said teachers worked a minimum of 50 hours a week to do the required work.
She said the school holidays were hardly a break as planning, reflections, and professional catch-ups had to be done during this time as there was not enough time during the term.
She said with fewer people drawn into the career and more leaving, the strain and workload put on teachers had become large - particularly in Rotorua.
Otonga Road teacher Matthew Liley said he was getting frustrated as he had high hopes the Government would solve the issues, "but we just don't feel they're listening".
Liley said increasing teacher aides in classrooms would help teachers greatly and that was not addressed in the offer.
NZEI Rotorua branch president Jo Collyer said it was not about money, but a lack of time and resources to do what was needed.
"Children are going to fall through the cracks and we are going to be the ones to blame for it but the reality is we can only work within the system that's provided for us.
"It's time that the Government puts in the resourcing to ensure those things can happen more within school time.
"If the resources aren't put into education then children are going to suffer."
Selwyn Primary School principal Peter Barker said he thought the offer did not address any of the issues the sector was facing.
"We're in crisis here with record low numbers of people entering teacher training and an ageing teaching population."
The retention and growth of the teaching body were what he said was needed to make things better for learning.
Sunset Primary School principal Eden Chapman said the ministry had "pretty much given the same offer three times in a row".
"Unless some of the changes are added that we're requesting ... we can't deliver the strength of education needed."
Ministry of Education deputy secretary for early learning and student achievement Ellen MacGregor-Reid said the ministry was taking the concerns of teachers seriously both through collective negotiations and with wider work of the Government to invest in education.
"It's important to remember the almost $700 million on the table to settle these pay negotiations sits within a much wider Government education work programme, which will benefit principals and will benefit teachers.
"Already, this work programme has delivered nearly half a billion dollars of learning support and removed National Standards (something teachers said contributed to workload demands)," MacGregor-Reid said.
"Primary teacher retention remains high and provisional data for 2018 shows an increase of new beginning primary teachers entering the workforce alongside an increase in enrolments in teacher training.
"The Government's investment to boost teacher supply is progressing well, including awarding 165 TeachNZ scholarships for primary teaching careers, allocating 230 grants to assist graduates into their first roles and helping more than 1300 teachers either return, or remain teaching by enrolling in the Teacher Education Refresh programme.
"We have also had more than 1100 qualified teachers from overseas screened and made available to principals for interviews. There have been 271 teachers accept roles, of which more than half are primary," she said.
Had the latest offer been accepted, more than 30,000 primary teachers would have received a 3 per cent pay rise every year for three years, and access to higher maximum steps in the pay scale.
They were also offered the option to either bring forward access to the new top pay step by 12 months, or have extra classroom release time.
The first option would have seen 9700 primary teachers get $6973 more in their pay after 12 months, increasing to almost $10,000 after 24 months.
The second option was for 10 hours of additional classroom release time for the majority of teachers, every year for three years.