Māori have criticised the Treaty of Waitangi provision in the Trans-Pacific Partnership (TPP) and don't believe it can protect their interests.
The Waitangi Tribunal has been told that Māori should not have to rely on a clause in the trade agreement anyway.
It is holding an urgent inquiry in Wellington this week, which began today with opening submissions and evidence from claimants expert witnesses.
The tribunal is seeking to determine whether provisions in the TPP effectively protect the interests of Māori (see the clause below).
Claimants lawyer Bryce Lyall said a key point was that Māori have no effective voice in that decision.
"Nor would they have an effective voice in any ISDS (investor/state dispute settlement) process that may arise."
Counsel Alana Thomas said Te Rūnanga a Iwi o Ngāti Kahu had no confidence in the Crown.
"Given past dealings with the Crown, the Crown can not be trusted to uphold its duties and its obligations to its Te Tiriti partner to activate and give practical effect to this clause."
Auckland University law professor Jane Kelsey said it was fundamentally problematic in terms of the treaty that Māori had to rely on a clause to protect their interests in the first place.
She said the phrase in the clause that mentioned the government's capacity to provide 'more favourable treatment to Māori' was ambiguous.
"Not only is it not defined. There is no clear comparator. More favourable than what?
"It is a real problem when there is no comparator because you invite all sorts of creative interpretations."
She said the second paragraph of the provision makes no specific reference to investor state dispute settlement, which was a problem.
"If I was an investor, I would have a field day in running that argument."
Māori Council lawyer Peter Andrews said its claimant was also taking issue with that particular phrase.
"The phrase determines the scope of the application to measures adopted by the Crown to promote Māori interests."
Mr Andrews said there was also concern that the clause only 'kicked in' if the Crown decided to take action.
About 20 counsel are attending the hearing, representing a range of claimants, many from Northland.
Tomorrow, evidence will be heard by claimant witnesses Haami Piripi and Maanu Paul and Crown official Penny Ridings.
The inquiry will run till Friday.
TPP Article 29.6: Treaty of Waitangi
Provided that such measures are not used as a means of arbitrary or unjustified discrimination against persons of the other Parties or as a
disguised restriction on trade in goods, trade in services and investment, nothing in this Agreement shall preclude the adoption by New Zealand of measures it deems necessary to accord more favourable treatment to Maori in respect of matters covered by this Agreement, including in fulfilment of its obligations under the Treaty of Waitangi.
The Parties agree that the interpretation of the Treaty of Waitangi, including as to the nature of the rights and obligations arising under it, shall not be subject to the dispute settlement provisions of this Agreement. Chapter 28 (Dispute Settlement) shall otherwise apply to this Article. A panel established under Article 28.7 (Establishment of a Panel) may be requested to determine only whether any measure referred to in paragraph 1 is inconsistent with a Party's rights under this Agreement.