National leader Judith Collins predicts greater co-governance for Māori under the leadership of Prime Minister Jacinda Ardern, which she strongly opposes.
Collins' concern is based on an un-redacted version of He Puapua, a report commissioned by the Government in 2019 that sets out a roadmap to co-governance between the Crown and Māori by 2040.
It proposes a Māori Health Authority and Māori wards in councils, which the Government has acted on. It also suggests separate court and justice systems and a Māori Parliament or Upper House.
In a speech to National Party supporters over the weekend, Collins called for a public conversation about the proposals in the report before any more of the recommendations are implemented.
"If Labour believes that the Treaty intended two systems for everything, and that this is the model we want in 2021, then this is a fundamental change to our society. We cannot accept this via a health reform, via Māori wards, and via justice changes," she said.
"It has to be a national conversation, one that has honest, respectful and open debate - a debate where every voice is heard. A clear vision for where it leads, and one that goes to a referendum if needs be. It cannot be snuck through."
Collins doubled down speaking to Magic Talk on Monday, saying there are signs that Labour under Ardern will forge ahead with more co-governance systems.
"I'd say she's on that path," Collins said. "It's simply intolerable that we're going down this path without any decent conversation with New Zealanders.
"This is not good for Māori; this is not good for any New Zealanders. It is simply something that is thought up by people with absolutely no understanding or care for this country."
The He Puapua report was commissioned after New Zealand endorsed the United Nations Declaration on the Rights of Indigenous Peoples in 2010, under the leadership of former Prime Minister John Key - Collins' former boss.
It acknowledged that Māori hold a special status as tangata whenua, the indigenous people of New Zealand, and have an interest in all policy and legislative matters.
"It is non-binding and that's the point," Collins said, when asked if she agreed with National signing up to the declaration. "If you really read into it, it's really about indigenous people being able to protect their language and culture and their lands.
"We've dealt with all these things with the Treaty of Waitangi, we've dealt with them with the settlements; it is time for us to think where we move now and where we move now is not the He Puapua vision the Government is already starting to implement with the Māori Health Authority and Māori wards in local government."
While the He Puapua report was commissioned by Cabinet in 2019, it has not been approved by Cabinet and so does not represent Government policy.
When asked about the report in Parliament last month by ACT leader David Seymour, Ardern said the Government has "no intention of making such a constitutional change" as establishing a Māori Parliament.
"However, we do commit ourselves to making sure that we are upholding our obligations as Treaty partners by making sure that, for instance, we have the same ability for Māori to be housed, to have job opportunities, to have decent health outcomes - all of which, we have a long way to go," she said.
"I would hope that the member would see those as responsibilities that this Parliament, collectively, needs to act on."
Collins has vowed to reverse the "undemocratic" law that scrapped the ability for Māori wards to be overturned by a local poll, if National wins the election in 2023. Collins says it was unfair of Labour not to campaign on it.
She has also promised to scrap the Government's huge health sector shake-up, likening the proposed Māori Health Authority to "segregation" of last century.
Māori Party co-leader Debbie Ngarewa-Packer said Collins used the term segregation to "race-bait", telling Newshub it was "probably the lowest of lows I've seen Judith go".
Collins told Magic Talk her views have nothing to do with dog-whistling.
"I think people who know me know that I am a lawyer who cares very deeply about our constitutional arrangements. I care about democracy."