A background paper for PPTA delegates says the top of the basic pay scale needs to jump by 14.5 per cent, from $75,949 to $86,967, to restore top teachers to the same relativity of 81 per cent above the median income of all wage and salary earners that they achieved after their last big pay rise in 2001-02.
It says the pay rise and a reduced workload, particularly for middle managers such as department heads and deans, are needed to overcome severe teacher shortages in high-cost areas such as Auckland and in subjects such as maths and te reo Maori.
"The last settlement [in 2015] cost the Government $30 million to $40m extra in secondary teacher remuneration each year," the PPTA paper says.
"Pay increases of considerably more than those achieved in the last three rounds, as well as extra non-contact time and other conditions improvements, would make the cost of this claim significantly higher - into the hundreds of millions per year.
"We will need a strong membership commitment to achieving these aims and a willingness to undertake significant industrial action."
NZEI general secretary Paul Goulter also warned his members: "We will most likely be looking down the barrel of industrial action."
As well as a general pay increase, the PPTA paper proposes "a mechanism to address supply issues in areas where the median house price exceeds seven times the top step of the trained teacher base salary scale, or where the school is in a hard to staff district".
Based on the current top basic rate of $75,949, teachers would get an extra allowance when median house prices exceed $531,643.
PPTA president Jack Boyle said the extra allowance would not be a permanent "Auckland loading" similar to one that applies to public service jobs in London - a differential unions have resisted here to be fair to all workers. If house prices fell and basic teacher salaries rose, Auckland might not need the allowance in the future.
He said the actual level of the allowance would need to be realistic.
The PPTA has calculated that it would need to be $70,000 a year to fully compensate for Auckland house prices.
"There is absolutely no way that that's going to happen," Mr Boyle said.
Tauranga Boys' College principal Robert Mangan said generally teachers at the boys' college had been reluctant to take strike action in the past.
He said he could not comment on whether teachers should have a 14.5 per cent increase without any prior knowledge.
"I would support the salary increase, but I could not put a figure on it," he said.
He said there needed to be paid union meetings to consider what options were available for teachers.
Mr Mangan also said it was premature to say there would strike actions among teachers and those suggestions were "alarmist comments".