WELLINGTON, July 3 - New Zealand's teachers are among the most highly trained, best qualified and most experienced in the world, an international survey shows.

The Teaching and Learning International Survey asked teachers of Year 7 to 10 students from 34 countries about their schools and their work.

Education Minister Hekia Parata says more than 2800 teachers from 163 schools took part in New Zealand.

The survey showed that:

- 99 per cent had completed a teacher education or teacher training programme compared with an average 90 per cent of their overseas counterparts

- 97 per cent have participated in at least one professional development activity in the previous 12 months, compared with an average 88 per cent in the other countries surveyed

- The typical New Zealand principal had spent an average 12 years as a principal and had 26 years teaching experience, compared with the international average of nine years as a principal and 21 years teaching experience

- New Zealand teachers work an average 44 hours a week. That's six hours more than the international average and one hour more than the average in Australia

- The average class size for Year 7 to 10 students in New Zealand is 25, one student more than the international average.

"Teachers feel more valued here than teachers in many other countries surveyed," Parata said.

"Our teachers are also more likely to believe that they can help their students value learning and think critically."