One in five secondary schools has axed a subject because of a lack of staff, and half have teachers working outside their areas of expertise, a survey of more than half the country's secondary principals shows.
The survey by the Secondary Principals Association and the Post Primary Teachers Association found 56 percent of respondents in Auckland were experiencing problems or significant problems finding staff in a range of areas, compared to 26 percent for the rest of the country.
It also found 51 percent of Auckland principals had made sub-optimal teaching appointments compared with 35 percent in the rest of the country, and 20 percent of Auckland principals said they had increased class sizes because of the lack of teachers.
Auckland principals rated increased pay as the most important thing the government could do to alleviate the teacher shortage, followed by accommodation support and reducing teachers' workloads.
More than half the respondents said there were current problems in their schools in the science and maths areas, and with finding relief teachers.
The survey was sent to 418 principals and 219 answered, including 45 in Auckland.
PPTA Principals Council chairperson James Morris said the survey showed the situation was reaching crisis point and official vacancy figures did not show the scale of the problem.
He said schools were making compromises in order to get by and those measures would impact education quality.
"The sorts of things that they are doing is having teachers taking over classes that are outside their subject qualifications, they're combining year-level classes, they may be choosing to run a number of larger classes and in some cases not running some subjects at all," Mr Morris said.
He said the government's move to extend a bonding agreement to new teachers who worked for at least three years at Auckland schools was a good start, but he warned it might create problems in other parts of the country.
"What the survey shows is that the supply issue is right across the country and that by fixing it in one place it actually tends to draw the problem from somewhere else."
Mr Morris said the government needed to ensure teachers' pay and conditions were good enough to help recruit and retain the best teachers.
It should also make it easier for people in other professions to retrain as teachers, he said.
The principal of Macleans College in Auckland, Byron Bentley, told RNZ the staffing situation was the worst he had ever seen.
"For example, mathematics we've had 39 applicants and really only one fits the quality criteria that we would use for employing," he said.
Mr Bentley said he was told of three upcoming vacancies at his school in the past week and he was not confident about filling them.
House prices, travel and the cost of living in Auckland had contributed to the situation, as had a declining number of people graduating from teacher education programmes.
Mr Bentley said people needed a bigger incentive to become teachers.
Onehunga High School principal Deirdre Shea said the average number of applications for vacancies in non-shortage areas at her school had fallen from more than 100 to about 10 or 20.
She said the long-term solution to the shortage of teachers involved better pay for teachers and higher status in the community.
Pauline Cleaver, the Education Ministry's acting deputy secretary early learning and student achievement, said the survey results echoed other reports that it was increasingly difficult to recruit teachers.
"Our data shows that the total number of teacher vacancies is increasing and that numbers are rising faster in Auckland where there is considerable population growth," she said.
Ms Cleaver said the government had already announced a range of initiatives to ease the pressure on teacher supply.
They included a $9 million package last year focused on increasing the supply of secondary teachers, expansion of a school-based teacher training course, an reinstating relocation grants for teachers from overseas.
"Work is also underway to progress a workforce strategy that provides more real time information so we can better meet the future needs of schools," Ms Cleaver said.
She said any school facing a reduction in subjects or a less than 'optimal' appointment should contact the ministry's recruitment agent for assistance.