Education Minister Anne Tolley is backing Auckland Grammar's headmaster - despite him rebelling against our national qualification.

She's so happy with what John Morris is doing that she suggests he might be "way ahead" of everyone else in some of his thinking.

Ms Tolley has put an end to speculation over whether Grammar's decision to have the majority of its Year 11 students sit Cambridge International Exams instead of NCEA is legal.

Questions were raised this week over whether Grammar was breaching the Education Act which says schools must offer a "nationally and internationally recognised qualifications system", such as NCEA.

The ministry has said the Cambridge exams do not meet that requirement as they are not nationally recognised.

But Ms Tolley disagrees, saying they are accepted by all universities.

She says that the Auckland school is offering NCEA to those who want it, even though it will be only a handful of Year 11 students.

Ms Tolley got behind Grammar and its board, saying "where's the harm?".

She said New Zealand's education system gave schools the flexibility to offer students different options.

Grammar - which introduced the Cambridge exams 10 years ago but is now increasing the number of Year 11 boys sitting them - was using options that seemed to work for its students.

"I think that as John Morris has said, boys in general seem to respond better to the competition, and a test, that something like Cambridge provides.

"It focuses the boys' minds, it's grabbing their attention and they are performing well - that's what we want, that's what's important."

Ms Tolley said the "most important thing" was the fact the boys' parents appeared to be happy with what was happening and the students were succeeding.

"We also need to be making sure our kids are competitive internationally and Cambridge does that. It is internationally recognised so in some ways perhaps John Morris is way ahead."

The minister said she was not knocking NCEA.

"We talk about skills that are needed for the 21st century, and NCEA has been designed with that in mind and I think that's why it's a really good qualification and the research is starting to confirm that."

Ms Tolley said most high schools used NCEA and she wasn't worried about the few that also offered Cambridge.

"I just don't think it's a problem if a few schools want to stretch a particular group of students."