Few indigenous groups around the world - let alone southern Maori - would pass a threshold test for customary title, a Maori legal advocate says.
The Maori affairs select committee released the Marine and Coastal Area (Takutai Moana) Bill last week.
A repeal of the Foreshore and Seabed Act, the Bill would give Maori the right to take customary title claims to court.
However, claimants who could not prove exclusive use and occupation of land since 1840 would be excluded.
Despite being welcomed by Attorney-general Christopher Finlayson, the legislation has been rejected by Ngai Tahu as not going far enough.
"We had hoped the review and replacement process would produce a durable and fair outcome for iwi and the nation. It is disappointing that this second attempt at resolving the issue so closely resembles Labour's scheme and that we have not progressed far enough," Te Runanga o Ngai Tahu kaiwhakahaere Mark Solomon said.
He was concerned the select committee did not have adequate legal advice, with the threshold test for customary title a major concern for iwi,Ngai Tahu Maori Law Centre senior lawyer Desiree Mahy, of Dunedin, said she did not believe the changes went far enough.
"Ngai Tahu are going to have a difficult time making a claim under this Act. The minor changes will have no effect on that.
"The Bill is overly onerous and the test too high for all Maori."
Proving exclusive use and occupation since 1840 would be difficult as Ngai Tahu had been for many generations "nomadic in nature".
"Few indigenous groups anywhere in the world would meet this test."
