Nobody owns the water but Maori owned the rights to it, says Rawiri Taonui, adjunct professor of indigenous studies at AUT.
Prime Minister John Key's claim that no one owns fresh water - which derives from the Roman principle of "negative community" on sea water, fresh water, air and wildlife - is a philosophical misconception when unqualified. It is like saying no one owns the planet - true, but everyone can own land.
Governments exercise a sovereign right akin to ownership over fresh water. Landowners have water rights and commercial enterprises sell water.
One cannot help oneself to water in another country, hook a hose up to a farmer's irrigation scheme or take bottled water on supermarket shelves without permission, payment or both.
Pre-European Maori lore reflected a similar duality. Wai Maori (fresh water) belonged to the Mother Earth, Papatuanuku, and other deities, while tribes wielded mana akin to ownership encompassing spiritual, cultural, management and commercial rights.
When the first European ships called to trade for food, they also traded for water.
These pre-existing pre-European rights fall under the common law doctrine of Aboriginal or customary title, which applied when the first British settlers arrived and which the Court of Appeal recognised as continuing in the 2003 foreshore case.
They are also recognised in the Treaty of Waitangi which, pulling the two versions together, guaranteed Maori the exclusive and undisturbed ownership of lands, forests, fisheries, estates and taonga. Fresh water is a taonga natural resource.
The key issue underpinning current debate concerns how the Crown obtained its authority. If the Crown alienated Maori rights fairly through agreement or purchase there is no problem. However, if the Crown assumed authority without properly dealing with Maori rights, those rights continue to exist.
This is the same principle that underpins Maori claims to land, forests, fisheries and the foreshore.
The Maori Council claim before the Waitangi Tribunal will provide a seminal opinion on Maori water rights, which is lacking in New Zealand.
Apart from including the usual references to the Treaty, principles in common law and New Zealand history, a report will make international comparisons. The United States and Canada have recognised water rights in several treaties and settlements.
The past two decades have seen intense global debate on indigenous water rights. The International Covenant on Civil and Political Rights, the International Covenant on Economic, Social and Cultural Rights, ILO 169 Convention, the Declaration on the Rights of Indigenous Peoples, and the Convention on Biodiversity support indigenous water rights.
The UN-endorsed World Commission on Dams, World Water Council through the Kyoko Principles, Agenda 21 and the Rio Declaration have recognised such rights.
Three precedents in the past two years have direct bearing on New Zealand. Aboriginal peoples in the Northern Territory, the San people in the Kalahari Desert and the Aymara peoples of Chile have been accorded priority over commercial developments or granted commercial rights themselves.
Prominent Treaty lawyer Mai Chen has pointed out that successive governments have sought to avoid Maori fresh water claims. Mr Key's altering of section 9 in the State Owned Enterprise Act this year now appears as one such attempt.
More recently, Finance Minister Bill English has been at pains to separate the water issue from the sale of state-owned assets, which is like saying swimming has nothing to do with getting wet.
It is difficult to grasp how building a dam across a river does not affect water. The motivation here is $6 billion. National wants the cash, Maori can take the bag later. It is a case of money before human rights.
If the Maori Council claim succeeds, three outcomes are possible. The Prime Minister might ignore tribunal recommendations and an injunction can be sought halting asset sales due to begin in two months. Or the Crown could pass legislation limiting Maori rights as it did with the foreshore, which would spark a protest. Or the Crown can work with the iwi leaders group to put together settlement packages. Mr English has already indicated preferential shares; Mr Key has talked about a buyback of shares.
Maori face their own challenges. The Maori Council is fronting the fight ostensibly on behalf of all Maori. Many iwi leaders have not supported the action, believing they carry the mandate for all Maori.
However, neither has a clear mandate, with fewer Maori voting in council and iwi elections than either the general or local body elections.
I hope both want to avoid the decade long post-Sealord squabble that enriched the legal community to the tune of $20 million.
The Maori Party might consider the probity of their relationship with National.
Earlier in the year, Mr Key has been glib about Maori claims, derided the significance of section 9 in the State Owned Enterprise Act to the chagrin of the legal community, dismissive of possible settlements writing off allocating shares as Mr English suggested, and trivialised the tribunal. Each is less than the good faith expected of a Treaty partner.
Maori claims to fresh water are in the interests of all New Zealanders. Selling these assets to foreign buyers may reduce our mana and control of an increasingly premium resource.