Principals and a Māori language advocate are angry and disappointed by the Education Ministry's treatment of te reo Māori and the secrecy that has surrounded it.

Multiple Education Ministry whistleblowers have told RNZ this week that managers told them to delete the term Aotearoa and other Māori words from official documents.

They say managers always gave the instructions verbally and refused to put them in writing even when challenged to do so.

Some Māori terms were restored in final curriculum documents - but Aotearoa was apparently banned as a synonym for New Zealand.

The claims accompanied allegations ministry managers instructed staff on more than one occasion not to write down information because it could be obtained under the Official Information Act.

Māori language advocate Stacey Morrison said the word had its origins in the discovery of New Zealand by Kupe and his partner Hine-te-aparangi.

"The story that we hear from the North is that it was Hine-te-aparangi who said 'he ao, he ao, he Aotearoa' - 'it's a cloud, it's a cloud, it's a long white cloud'," she said.

Morrison said Aotearoa shouldn't be controversial - it was widely accepted and used as a term for New Zealand and in the names of more than 2000 businesses.

She said removing the word from new school curriculums flew in the face of the over-arching curriculum framework which included a commitment to the Treaty of Waitangi.

"It's just one word that can give us a sense that that vision is being realised. It's really not asking much, but it's removal means a lot more," she said.

The Education Ministry has refused to explain why its managers refused to put in writing their instructions to staff to delete Māori terms.

But it has said Aotearoa was omitted from the new curriculums for consistency with the overall title - the New Zealand Curriculum.

"The curriculum is called The New Zealand Curriculum, and references within it generally use New Zealand. This approach has been taken to keep the terminology consistent throughout the document," it said.

Bruce Jepsen from Te Akatea the Māori principals association said the moves were part of a series of decisions sidelining Māori and heavily criticised by the Waitangi Tribunal recently.

He said he had been calling it out since it began and it added up to institutional racism.

"The question is who loses power, whose knowledge is being marginalised, whose voice is excluded and who's going to carry the consequences for these decisions," he said.

Jepsen said it was not good for anyone, least of all Māori.

"It's harmful, it's harmful for all tamariki, Māori and non-Māori alike, when a group is discriminated against," he said.

"There's going to be a second class of citizen happening if one language is put above another. It's dire and these actions are actually representative of a national disgrace."

Principals Federation president Jason Miles said he thought New Zealand had come further.

"There have been a lot of changes within our education system, for example te reo is becoming a part of our daily language not only in schools but across society and to have the word Aotearoa taken out is I think really sad," he said.

Education minister Erica Stanford has said her office did not ask for Māori words to be deleted and she said there were more Māori terms in the curriculums than ever before.

Miles said that was only because of strong reaction to the first drafts of the curriculums.

"There has been additions put back in but why as a country of Aotearoa should we be pleading for that to be put back in? It should have gone in from the start as of right," he said.

The Education Ministry said it took its responsibilities under Te Tiriti o Waitangi very seriously.

"We do not accept the characterisation that the curriculum development process sought to remove Māori language, knowledge or perspectives from the curriculum," it said.

"The final curriculum includes te ao Māori, mātauranga Māori, Te Tiriti o Waitangi and te reo Māori across all learning areas.

"Feedback on draft curriculum content showed many parents, educators and other submitters wanted te reo Māori, Māori perspectives and Te Tiriti o Waitangi to be appropriately reflected in what students learn at school.

"They told us these elements are an important part of New Zealand's context and identity and help students understand the country they live in.

"The final curriculum reflects that feedback by making sure students' learning reflects New Zealand's context and identity."