Settling the teachers' pay dispute could cost around an extra $135 million a year - almost as much, over four years, as a new Poseidon aircraft.
The Ministry of Education and both teacher unions have declined to provide costings of the remaining union claims, citing an agreement not to talk before a meeting with Education Minister Chris Hipkins tomorrow aimed at resolving the dispute.
The NZ Educational Institute (NZEI) said: "Ahead of Thursday's forum with the Minister we've agreed we won't be making any public statements."
NZEI's original claims included a 16 per cent pay rise over two years, reducing funded class sizes in Years 4 to 8 from 29 to 25, and funding for a learning support or special needs co-ordinator in every school.
Employment Relations Authority Chief James Crichton, who was called in to facilitate bargaining last November , said "the total cost of conceding their proposals was costed at around $2.5 billion".
"My prevailing impression of this facilitation is that NZEI came into the process with a series of proposals which taken in their totality had an air of unreality about them," he said.
But seven months later, after three full strikes and another partial strike on Tuesday, both the NZEI and the Post Primary Teachers' Association (PPTA) may be ready to settle for much less than they first asked for.
The ministry has offered both unions pay rises of 3 per cent a year for three years plus an extra step on their salary scales that would take the cumulative pay hike for many teachers to 12.6 per cent over three years - a deal the ministry costed last year at $1.2b over the four years (now three years) to June 2023.
PPTA president Jack Boyle has said the main sticking point for secondary teachers is now workload.
"You can't say that the ministry hasn't tried to do a bit of negotiation in the salary space. They haven't really in the workload space," he said last month .
NZEI wants action on teachers' workload too, and is also holding out for restoring "pay equity" - a 20-year-old principle that primary and secondary teachers with the same qualifications should be paid the same, which has been lost because of timing differences in the last pay round.
On workload, both unions lodged claims for an extra hour a week of classroom release time - a lift from one hour a week to two hours for primary teachers, and from five hours to six hours for secondary teachers.
That would be difficult to implement quickly. Hipkins told striking teachers at Parliament last week: "More classroom release time requires more teachers, and at the moment we have a teacher shortage."
To be precise, on the basis that teachers are paid to work 40 hours a week, it would require boosting the current 51,371 fulltime-equivalent teachers in state and integrated schools by one-40th, or 1284 teachers.
The ministry says primary teachers earn an average of $72,900 a year, or $35.05 an hour, and secondary teachers average $79,500, or $38.22 an hour, before tax.
Hiring extra teachers for one hour a week for every existing teacher at those pay rates would cost about $40m a year for primary teachers plus about $35m a year for secondary teachers.
On pay equity, primary teachers are now paid 3 per cent less than their secondary counterparts with the same qualifications, so restoring pay equity would require an extra 3 per cent pay rise for the 87 per cent of primary teachers who have at least a university degree, on top of the increases the ministry has offered to both unions.
Last week's Budget allocated $2.3 billion for primary teachers' salaries, so that extra 3 per cent for 87 per cent of teachers would cost about $60m a year.
Altogether, the extra class release time and restoring pay equity could cost about $135m a year, or $540m over four years.
For comparison, the Budget earmarked $1.7b over four years towards a total of $2.3b to buy four new Poseidon surveillance aircraft to replace the Air Force's ageing Hercules fleet, a cost of about $575m for each aircraft.
These estimates are only ballpark figures.
Former NZEI president Frances Nelson has suggested looking for a " creative solutions " to the workload problem, such as providing more paid teacher-only days, which would reduce teachers' class contact time without requiring more teachers, until more teachers can be recruited over the next few years.
The ministry has also said that "pay equity" should be interpreted as offering deals of similar value to primary and secondary teachers, so that if primary teachers want pay equity they would have to sacrifice something else such as higher pay for teachers without degrees.
Two things yesterday offered hopes for a settlement.
First, the ministry surprised the PPTA by deciding not to dock the pay of secondary teachers who refused to teach Year 9 students yesterday, saying it could no longer dock pay for a partial strike under a law passed in December.
And second, NZEI accepted a pay deal for learning support service managers providing pay hikes of 2 per cent ayear in 2020 and 2021 plus a new step in their pay scale. It said the deal would lift the managers' pay by $11,000 a year.