Ngāti Awa has lost its appeal in the High Court to stop Creswell New Zealand Ltd taking 1 billion litres of water a year from the Awaiti aquifer near Whakatāne.
The company, a subsidiary of Chinese soft drinks giant Nongfu Spring, plans to upgrade an existing water bottling plant in Ōtakiri to produce a maximum of 10,000 bottles an hour.
It also wants to build two new high-speed bottling lines, each producing 72,000 bottles an hour.
The Eastern Bay of Plenty iwi lost a previous appeal in the Environment Court last year.
A key issue was whether the Environment Court was required to consider the end use of plastic bottles, when the use of the bottles did not itself require resource consent.
The High Court concluded that the adverse effects of consumers discarding plastic bottles were too indirect or remote to require further consideration of Creswell's water-take application.
In its ruling, it acknowledged that the Environment Court did consider the cultural effects of exporting the bottled water and made two factual findings.
These include that "there is no loss of mauri from the water as the water remains within the broad global concept of the water cycle and is returned to Papatūānuku irrespective of where it is used, and that the exporting of the water did not interfere with the ability of Ngāti Awa to be kaitiaki."
The High Court said these factual findings were not susceptible to challenge on the appeal.
Creswell New Zealand managing director Michael Gleissner said in a statement the company welcomed the High Court decision to uphold consents to expand the existing water bottling facility.
"It is a thorough, thoughtful and substantial analysis of the issues under the appeal, and the company will now take time to consider the judgment in detail," he said.
Te Rūnanga o Ngāti Awa chief executive Leonie Simpson said it was an extremely disappointing outcome.
"We've invested a lot of time, effort and resources alongside our supporters who are our hapū and whānau of Ngāti Awa," she said.
"Our biggest concerns are what we took to the High Court around our ability to be kaitiaki of a taonga which is going to be put into plastic bottles and exported around the world.
"The other is the end use, so what contribution will billions of plastic bottles make to the climate issue that we are facing? What does that say about us as Aotearoa and what does it say about the tangata whenua of Aotearoa, particularly around a taonga."
The iwi is yet to consider further legal action, and will spend time reading through the judgment in detail.
Simpson said tikanga was often 'diluted' through the legal process, and concepts of mauri, mana and kaitiakitanga were often misunderstood because they were viewed through a narrow lens.
"Our tikanga and our kawa as tangata whenua are lateral, they are broad, they are interconnected, and when they are measured against frameworks and legislation and rules and regulation they become diluted and reduced," she said.
"When we have concepts of kaitiakitanga, te mauri o te wai, te mana o te wai, te mana ki te wai, those tikanga and kawa being presented in legal forums like this, they become reduced to fit in within the framework."
She said the appointment of Justice Joe Williams to the Supreme Court gave her hope for a New Zealand judiciary that can better consider tikanga and kawa, in a broader way, within legal proceedings.