The High Court has rejected the Maori Council's legal challenge to the partial sale of state-owned assets.
Corresponding action by a group of Waikato sub-tribes, Pouakani, has also failed.
Mighty River Power is the first company tagged for partial float by the Government, but that was delayed while the legal challenge took place.
In his judgement released on Tuesday, Justice Ronald Young said he is satisfied there is no connection between the sale of shares in Mighty River Power and the need to provide for Maori claims to water.
He said he is satisfied the consultation the Government undertook with Maori was adequate, and that there was no breach of natural justice in the process.
Finance Minister, Bill English, has welcomed the decision, saying it confirms the Government can go ahead with the partial sale of four state-owned energy companies.
He says the judgement is firmly of the view that the partial sales do not affect the Crown's ability to recognise rights and interests in water, or to provide redress for genuine Treaty of Waitangi claims.
The Maori Council says it will appeal against the ruling. The barrister acting for the Maori Council, Felix Geiringer, said it is disappointed but not surprised by the ruling and intends to appeal. He said Maori rights to water need to be resolved before the sale of Mighty River Power goes ahead.