In the recent Māori Land Court case Mercury NZ Ltd v Cairns Pouakani River Bed, Mercury, supported by the Attorney-General, sought to strike out an application made by Pouakani hapū relating to the Waikato Riverbed at Pouakani.

In 2019, hapū of Pouakani applied to the Māori Land Court for an order that the riverbed at Pouakani, which is currently used by Mercury for hydropower generation, is Māori customary land.

The application also sought a declaration that Pouakani hapū are the owners of the river water that flows over the riverbed. Mercury and the Attorney-General applied to strike out this application on the basis that the current titles, which are held by the Crown or Mercury, are indefeasible, and the Māori Land Court does not have the jurisdiction to determine interests in water.

This case raises important legal issues relating to Māori customary title and water ownership. As property practitioners, it is important to be aware of these developing areas of law, which may have far reaching implications, particularly for the property and resource management area.

Procedural history

Pouakani’s legal claim to the riverbed has already been subject to two Supreme Court decisions: Paki v Attorney-General (No.1) and Paki v Attorney-General (No.2).

The Crown initially asserted ownership of the riverbed on the basis that the Waikato River is navigable. If the river was navigable, ownership of the riverbed could be vested in the Crown under the Coal Mines Amendment Act 1903.

However, the majority of the Supreme Court in Paki No.1 held that the Waikato River at Pouakani was not navigable and therefore the Crown’s assumption of ownership under the Coal Mines Act was wrong.

In Paki No.2, the Supreme Court considered whether the Crown had instead gained title to the riverbed at Pouakani through the ad medium filum aquae presumption. According to this presumption, where a property is adjacent to a river the landowner of that property also owns the riverbed to the middle line of the river. In this case, the Supreme Court found the ad medium filum aquae presumption did not apply.

Neither case provided a clear ruling regarding the status of the riverbed, which is the subject of the present litigation.

Was Māori customary title to the riverbed extinguished?

In the Māori Land Court, the primary issue was whether the Court could declare land registered under the Land Transfer Act 2017 (LTA) to be Māori customary land. Mercury and the Attorney-General submitted that the Court cannot, and therefore the Pouakani application should be struck out. Mercury’s argument was based on the general proposition that once title has been registered under the LTA it becomes indefeasible, thereby extinguishing Māori customary title.

This proposition is supported by a number of cases, for example, in ANZ National Bank Ltd v Uruamo (2012) the Court held that if land is brought under the LTA any customary rights will have been extinguished.

The Pouakani applicants submitted that since they have retained continuous ownership of the river in accordance with tikanga, and titles were issued to the Crown erroneously, Māori customary title over the river at Pouakani has not been extinguished.

The Māori Land Court was not convinced by Mercury’s argument, noting that it is unclear whether a title that is wrongly issued under the LTA can defeat Māori customary ownership. The Court therefore considered that this aspect of the Pouakani application should proceed.

Ownership of the river water

The Pouakani application also seeks a determination by the Māori Land Court that they are the owners of the river water that flows over the riverbed at Pouakani.

In the strike out application, Mercury and the Attorney-General submitted that the Māori Land Court does not have jurisdiction to determine claims relating to ownership of water. This argument is based on the definition of “land” in the Te Ture Whenua Māori Act 1993 (TTWMA), which Mercury and the Attorney General contend does not include water. In addition, they suggested that no one owns the water that flows over their land.

The Pouakani applicants disagreed. They submitted that according to their tikanga, the river is treated as a whole, rather than separated into riverbeds, banks and water. Therefore Māori customary land under the TTWMA could be understood to include water that flows over that land. According to the Pouakani hapū, it is on this basis that the Māori Land Court can inquire into customary water rights.

The Māori Land Court noted that it is unclear whether it can inquire into customary water rights, or whether, as Mercury contends, its jurisdiction been ousted by the definition of land in the TTWMA. The Court therefore decided that this issue should be fully considered by the Court.


The Court declined Mercury’s strike out application as the Pouakani claim relating to the status of the riverbed was considered clearly tenable. Furthermore, the Court noted that water ownership is a developing area of law that is intertwined with tikanga elements and should not be struck out. The Pouakani application may now proceed for determination by the Māori Land Court.


The Pouakani application raises complex, and potentially contentious, issues relating to tikanga, Māori customary land, and ownership of water. These novel and developing areas of law may have substantial implications for property practitioners and are therefore important to be aware of.


Claire Tyler and Devon Tesoriero