Dismantling Te Aka Whai Ora - the Māori Health Authority flies in the face of all the work Māori health providers and iwi providers have done for better health outcomes, Māori health advocate Lady Tureiti Moxon says.
The government plans to introduce legislation to disestablish the authority in its first 100 days.
Lady Tureiti filed an urgent claim with the Waitangi Tribunal alongside Māori primary health leader Janice Kuka, citing concerns that the removal of Te Aka Whai Ora will result in prejudice in healthcare.
It comes days after an urgent complaint was filed by Tauranga iwi Ngāi Te Rangi for government moves to reduce the use of te reo.
Lady Tureiti told Morning Report Te Aka Whai Ora was created to bring about transformational change that supports the participation of Māori in the health system.
"On average Māori have the poorest health status of any ethnic group in Aotearoa, Māori are twice as likely to die from preventable diseases and Māori are twice as likely to face discrimination in health and are less likely to be referred for diagnostic tests," she said.
"The Crown have said the way in which the health system has been run previously was not working for Māori and certainly wasn't making a very big difference in the health of Māori."
Lady Tureiti said Te Aka Whai Ora at least has a good understanding of how to work with Māori, what the needs of Māori are, and listen to Māori.
"Now that's a big difference between what we've had previously, when we've been done to. They listen, we're able to co-design, we're able to work together and do things in a way that are actually conducive to the communities we work in.
"But unfortunately, everybody thinks that the Crown, or those in the government think that they're the only ones who know what's best for everybody and even though they say they've discussed this or they're working through this with iwi and others, it doesn't work, it never did work and it won't work because the government holds on to all that power and doesn't release it."
Prime Minister Christopher Luxon has said the government was considering the claim and would respond in due course.
He said the authority was suboptimal in its first year and that added bureaucracy would not help improve Māori health outcome.
The National Party committed to scrapping Te Aka Whai Ora before it had even been established.
Prior to the election, the party said it would replace it with a Māori health directorate which would sit within the Ministry of Health, but no commitment has been made since.
Days after his appointment as Health Minister, Dr Shane Reti told Checkpoint the government was getting rid of the authority "because I fundamentally and we fundamentally disagree with the ideology that says Wellington knows best, let's place half a billion dollars of Māori health provider contracts with the Māori Health Authority in Wellington".
Te Aka Whai Ora decisions were made in Wellington and the funding was based there, despite the fact the it might consult with iwi about these decisions, he said.
"I am comfortable that we will devolve decision-making and funding for Māori health as close to the home and as close to the hapū as we can."
Thousands of people have protested the new government's policies that affect Māori.
In response, Minister for Māori Development Tama Potaka said his government would work closely with iwi, Māori and other community leaders to try and get away from big bureaucracy solutions.
Potaka agreed there were some cultural disadvantages for Māori in areas such as health and housing.