Māori health leaders are calling on the government to scrap the Treaty Principles Bill, saying equitable healthcare is "a fundamental right".
The controversial bill is set to go through a six-month select committee process to get to a second reading Parliament. Both National and New Zealand First have said they will not be voting for it.
The Royal Australasian College of Physicians' (RACP) Māori Health Committee chair Dr Matt Wheeler said the principles outlined in the bill diminished "the constitutional status of the Treaty / Te Tiriti".
"This bill undermines the state's responsibility to collaborate with Māori, rendering the Treaty and its obligations meaningless," he said. "Consequently, equitable healthcare, a fundamental right for Māori, will continue to suffer."
A conservative estimate suggests the bill will cost about $4 million to progress to a second reading in the House.
ACT Party leader David Seymour has dismissed the analysis, calling the figures "fabricated".
Despite ACT's coalition partners stating their positions, Wheeler said the government collectively was accountable.
"I refer to it as the coalition government's bill rather than ACT's bill because the government of the day agreed to support it to its first reading, regardless of its potential success beyond November," he said.
"The RACP has grave concerns about the bill's direct and indirect impacts on people's health. Questioning the 'principles' of the founding document emboldens racism and causes stress which can lead to a range of health problems.
"No matter the outcome, the mere progression of this bill is already causing harm."
Advice provided to Cabinet from Ministry of Justice officials and contributing agencies recommends the coalition continue the status quo, rather than redefining the principles.
Wheeler said the bill represented another setback for Māori health after the disestablishment of the Māori Health Authority.
"The Royal Australasian College of Physicians urges the coalition government to abandon the Treaty Principles Bill and focus on uniting New Zealanders, rather than driving them apart," he said.
"In the words of the late Kiingi Tuheitia: We should use this time to build kotahitanga. We need to be united first, and then we decide our future."