The national body representing most Maori immersion schools has little faith in National Standards data issued by the Government.
That's in spite of the data including some positive results for kura kaupapa.
The National Standards results for 2012, which were released on Tuesday, for the first time included information about Maori-medium schools.
Nga Whanaketanga Rumaki Maori, which examines kura, said it shows kura students writing in Te Reo are achieving at the same level as mainstream students writing in English, namely, 70% are at or above the National Standard.
Te Runanga Nui o Nga Kura Kaupapa Maori o Aotearoa chair Toni Waho said the results are positive as far as they go.
But he said students' learning achievements in Te Reo are not reflected because it doesn't take into account that the language is not the language of most of the students' homes and communities.
Mr Waho said many of them have acquired the language at kohanga reo and kura.