Secondary school principals have told the secondary teachers union they are facing a staffing crisis due to a lack of New Zealand teachers.

The Post Primary Teachers' Association said secondary principals responding to its annual staffing survey reported unprecedented shortages.

It said one in four of the 127 respondents said they had cancelled classes because they could not find a specialist teacher.

They also reported that from mid-October last year to late March this year vacancies attracted an average of 1.6 New Zealand applicants - less than half the pre-Covid figure of 3.4, and much lower than 10 years ago when schools received an average 9.9 New Zealand applicants for every position advertised.

"The normal experience of principals was not having a choice in selecting applicants from New Zealand because there were either none (33 per cent for classroom jobs) or only one (31 per cent)," says the survey report.

The report says one-third of positions the principals have advertised could not be filled and 5 per cent are filled by getting a Limited Authority to Teach for a person who is not a registered teacher.

It says 48 per cent of the principals say they are employing untrained or unqualified teachers because they can't find trained and qualified staff.

Principals told the survey "staffing is at crisis point", "the situation is dire" and "I think we are in a crisis".

"Advertisements for jobs are having to be re-advertised multiple times before we get a worthwhile candidate," a principal told the survey.

"We have hired three times from overseas in the last year and each time had problems, one did two weeks and then resigned calling in sick for all of their notice period, one declined the job two days before they were due to start, and the other one we are still awaiting the visa to be approved."

Another wrote: "It is so stressful, much more stress than Covid as I cannot see a way I can staff my school. I have three teachers going on maternity leave and do not have much hope of finding a replacement. It keeps me awake at night."

PPTA acting president Chris Abercrombie says the results show the secondary teacher shortage is beginning to have a serious impact on secondary education.

"Every student deserves to have a specialist teacher, someone who knows the subject inside out, can stretch students and enable them to grow their knowledge and skills in that subject.

"The fact that the teacher shortage has got this serious is an indictment on governments present and past. It must and can be reversed."

Abercrombie says secondary teachers should have much better pay and conditions.

-John Gerritsen/RNZ.