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."
RNZ has approached Seymour's office for comment.