Auckland secondary school teachers say the gap between their pay and the city's house prices will lead to teacher shortages.
At the Post Primary Teachers Association (PPTA) conference in Wellington, teachers told Radio New Zealand they can no longer afford to buy houses in Auckland.
They said it was becoming harder to find teachers for new jobs in the city's growing schools, and to replace those who were retiring.
PPTA West Auckland chairperson Melanie Webber said Auckland schools would find it increasingly difficult to hire teachers.
"The impact, if nothing is done about this, will be a teacher shortage in Auckland. If you get paid the same amount of money to teach in Auckland as you do elsewhere, people will go elsewhere. We'll also have an issue with people not staying in teaching. We need to start looking at Auckland supplements for some key professions."
Ms Webber said the buying power of teachers' salaries had eroded in the past 30 years.