Christopher Luxon launched an anti-bureaucracy attack and laughed off a potential coalition partner's claims he was scared of tough issues.
Act Party leader David Seymour has demanded a referendum on co-governance but Luxon rejected the idea today.
Seymour said National Party leader Luxon should keep an open mind "and not run away at the first sign of controversy".
Luxon laughed off suggestions his refusal to back a referendum meant he was afraid of the issue.
"I've been really clear on that. We're not ready for a referendum right now because we're not clear about what we're actually talking about."
He said the definition of co-governance had changed over time.
Co-governance very broadly described arrangements for governments to share decision-making with iwi or other groups.
The Government has been considering steps in developing a plan to realise United Nations obligations around Māori self-determination.
"We are ruthlessly obsessed in the National Party about improving outcomes for Māori, non-Māori, everybody in this country," Luxon said.
"But the way to do that is not to create two separate systems. That creates massive amounts of bureaucracy."
He added: "That's why we're against Three Waters, that's why we're against Māori Health Authority, because bureaucracy gets in the way of delivering outcomes.
"We're seeing it with this Government on literally every single topic at the moment."
Luxon said the Government had added "14,000 bureaucrats here for two billion dollars a year" to no avail.
He seemed to be referring to 14,000 additional public sector employees hired since 2017, a topic his colleague Simeon Brown raised in the House last year.
"Pick health, pick education, pick mental health, pick poverty. We haven't got better outcomes," Luxon said.
"We want results, we want outcomes...You don't do that creating two systems and creating massive bureaucracies."
Luxon earlier said it was the Government's job to explain what co-governance meant nowadays.
And Māori Crown Relations/Te Arawhiti Minister Kelvin Davis agreed when asked if the Government should do more to educate people about the meaning of co-governance.
"It probably is the role of the Government. Those people who know and have been involved in co-governance understand that it is a very powerful tool to improve outcomes for people, in particular Māori."
Davis said many sectors of society were probably not knowledgeable about co-governance.
"We've got to make sure that people aren't ignorant of what co-governance brings and it's an important future direction for Aotearoa."
Davis said the new school history curriculum could help people better understand how Māori and other ethnicities worked together.
'He has disregarded our voice and continued with this divisive kaupapa.'