Education Minister Hekia Parata's office says it has cleaned up its act after a row over teacher privacy.
In May Waitara High School teacher Dawn Laurence wrote to Ms Parata criticising the proposed increase in class sizes - a policy which was later scrapped - and Ms Parata replied to the school's board of trustees with a copy to Ms Laurence.
In August Labour's Chris Hipkins questioned Ms Parata in parliament and said other teachers who had complained were treated in the same way.
Ms Laurence complained to the Privacy Commission and has been told that in future Ms Parata's office will respond only to the teachers who write letters of complaint, Fairfax reports.
Ms Parata's office says the rule was changed "months ago".
Mr Hipkins has accused Ms Parata of bullying teachers by going over their heads and writing to their schools.
"It certainly wasn't an isolated incident, I understand she did it to a number of teachers," he said on Radio New Zealand on Monday.