Registration body the Teaching Council is being investigated over its management of procurement and conflicts of interest.
The Public Service Commission told RNZ that Education Minister Erica Stanford asked for an independent investigation after receiving a complaint.
The commission said it began its work after finalising terms of reference on September 8 and expected to complete a report by December.
The chair of the Teaching Council's governing council, David Ferguson, said no staff had been stood down while the investigation took place.
Asked to confirm the actions that were the subject of the inquiry, Ferguson said in a statement the council could not provide any details while the process was under way.
RNZ has asked Stanford's office for comment.
The council is responsible for registering teachers, setting professional standards and approving teacher education programmes. It is required to enhance the status of teachers and identify and disseminate best practice.
Annual reports showed the council received $20.8 million last year and spent $18.8m.
The council recently launched a campaign "Teaching shapes what matters most."
It told teachers the campaign "challenges outdated views of teaching and celebrates the deep expertise, skill, and impact that define your work".
"This work is one part of our wider commitment to 'strengthen the mana of teaching, so teachers can change lives.'"
The council also developed new professional standards for teachers taking effect next year.
