A Northland principal says legislation passed this week is likely to stop teachers from airing concerns about education policy.

The Education Amendment Bill, which replaced the Teachers' Council with a new body called Educanz, passed its third reading in the House .

President of the Tai Tokerau Principals' Association Pat Newman said the code of conduct in the bill could prevent teachers from criticising the ministry.

He said that posed an ethical problem.

"Because as teachers, whether the Minister likes it or not, we have a code of ethics that says we have a responsibility to stand up for the needs of our children.

"And that straight away runs contrary to the code of conduct that says you can have all these concerns, but don't say them in public."

He said under the new act, the Minister of Education will appoint all the members of Educanz - making teachers the only professionals who cannot elect their own national disciplinary body.