Post Primary Teachers' Association (PPTA) president Robin Duff says the Ministry of Education "has its head in the sand" over looming teacher shortages.

Secondary staffing was approaching crisis level, Mr Duff said.

A recent survey commissioned by the association found staff shortages a common problem and serious concerns from respondents.

The figures confirmed an online survey conducted by education sector union NZEI Te Riu Toa last month, which found primary and intermediate schools facing staff shortages.

The two surveys contradicted comments made last month by Education Minister Chris Carter, who said schools were coping well with the tight labour market.

Mr Duff said secondary schools faced an aging workforce, a lack of qualified job applicants and a growing resignation rate.

Some had been forced to cancel courses because of a lack of teachers.

The survey, of 184 schools, found 22 percent had advertised vacancies they were unable to fill, 20 percent had vacancies temporarily filled by untrained and unqualified relievers, and 3 percent had vacancies permanently filled by untrained and unqualified appointees.

Mr Duff quoted from principals responding to the survey, who expressed concerns over recruitment.

One said there was "a real shortage" in graphics and hard materials technology teachers. Another said staffing in secondary schools appeared to be at "crisis level".

Recruitment was harder, and teaching was becoming a less attractive job for "quality young people".

Mr Duff said he hoped the results of this latest survey would "serve as a wakeup call to the ministry".

The survey found 75 percent of jobs advertised had no choice of candidate, either because there was no, or only one, applicant; 28 percent of schools surveyed were forced to use teachers outside their subject area because they were unable to get trained and qualified subject specialists; and 16 percent of schools had to transfer or cancel courses because of a lack of qualified staff.

Principals were concerned over the quality of appointments schools were forced to make, due to the low number of applicants.

The PPTA staffing report was the result of a survey sent to principals in term one this year. Replies came from 184 schools -- 44 percent of those who received the survey.