AUCKLAND, July 30 - Despite New Zealand Educational Institute's claims that schools are being swamped by beginner teachers, high schools are struggling to recruit new staff, especially in science, maths, technology and Te Reo Maori, the Post Primary Teachers' Association said.

The number of job ads for high school teachers are on the rise, and 47 per cent of them are being re-advertised - much higher than the 22 per cent figure for primary teaching roles, the association's president Angela Roberts said.

"The experience in secondary schools is very different from that in primary with regards to recruitment of teachers."

A survey found one in nine schools had to either cancel classes or use distance learning because a teacher of a certain subject couldn't be found, Ms Roberts said.

She says as high school teachers often have transferable skills, other career options may look more attractive given the low teaching salaries.

Her comments are in contrast to comments from NZEI on Tuesday which called on the government to tackle the "looming crisis of a massive oversupply of beginner teachers".

It said the government had known for years that there was an oversupply of newly graduated students but had done nothing about it.

NZEI national secretary Paul Goulter said many new teachers ended up employed on day-to-day or relieving jobs where they missed out on the professional development, skills and mentoring that would help them become great teachers.