Wellington iwi Ngāti Toa Rangatira is asking the ACT Party leader to bin the Treaty Principles Bill or front up to a public debate.
Te Rūnanga o Toa Rangatira chief executive Helmut Modlik said David Seymour has constantly challenged New Zealanders to have a national conversation about the Treaty of Waitangi but it was a charade.
Modlik said he wanted to take up Seymour's challenge, and organise a public debate in Porirua between the two leaders but he expected the offer would not be taken up.
"I'm disappointed by David's divisive rhetoric. Either stop the charade around a national conversation and debate and kill the Treaty Principles Bill now, or let's publicly debate what the Treaty means in the 21st century," he said.
Earlier this week at the Koroneihana celebrations in Ngāruawāhia both of ACT's coalition partners pledged not to vote for the Treaty Principles Bill past its first reading.
Modlik said with no other political parties backing the Bill it was time for ACT to abandon it.
Instead of a national conversation, Seymour preferred news soundbytes, carefully curated messages, and social media posts. His reasoning was being amplified by a range of affiliated political lobby groups and ideological supporters, he said.
"The information David and his backers are making public is one-sided and unfair. It's why I'm responding to his challenge for a national conversation by seeking a public debate, which we'd love to host in Porirua."
Modlik said he wants to debate what in the 21st century is a meaningful way of dealing with Te Tiriti of Waitangi that binds Aotearoa together.
"I've accepted [Seymour's] tacit invitation to participate in a national discussion and debate, and I look forward to having it with him so that we can actually put in front of our community, the whole of the nation, both sides of the story.
"One thing that I am grateful to both [Seymour] and his coalition for is that they have through their callous reversal of decades of truth and reconciliation, they have catalyzed a degree of kōtahitanga, unity that may be unique in our history."
In a statement David Seymour said he agrees with Modlik that a national conversation about our founding document was needed.
"The point of the Treaty Principles Bill is to protect all New Zealanders' say on the future of our country.
"There are going to be plenty of opportunities for this conversation to take place up and down the country over the next several months. Helmut has the same right as anyone else to take part in this process and I look forward to hearing what he has to say."