Ngati Porou is ruling out buying shares in Mighty River Power for now - because rivers in its tribal territory don't feed the power generator.
The East Coast iwi says it does not want to encroach on the rangatiratanga of other tribes.
Te Runanganui o Ngati Porou chairperson Apirana Mahuika said they have their own waterways to care for.
The Waiapu River is massively silted.
However, he said investments could be made in the future - if he received invitations from Tuwharetoa and Tainui.
But Mr Mahuika said any attempt to invest would be an intrusion.
He said that position could change when future generations are in charge.