The chief executive of Ngati Toa agrees a robust debate is needed on the Treaty of Waitangi. 

Helmut Modlik will debate ACT leader David Seymour tonight, two months after Modlik called him out. 

A draft of Seymour's Treaty Principles Bill will be ready for public release and discussion next month, but National says it will support the bill no further than the first reading only. 

Modlik told Ryan Bridge the country needs a national conversation about the treaty, which is why he agreed to debate Seymour. 

He says the country was only getting curated sound bite versions of one position. 

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