Decades of Treaty of Waitangi breaches by the Crown, are spelled out in the findings of a Waitangi Tribunal report on Lake Waikaremoana treaty claims.

The document is the fifth part of an overall report into Te Urewera claims.

The report says the late Sir Rodney Gallen, who had a long association with Waikaremoana kaumatua, wrapped up his evidence to the Tribunal with these words: 'The history of the relationship of the Crown to the people of Waikaremoana has been a sorry one for a very long time.'

The Tribunal found seven instances of treaty breaches arising from the Crown-Maori contest over Lake Waikaremoana, which it says resulted in prejudice to the claimants.

Those findings include examples of the Crown unfairly discriminating between tribes.

The report says the Crown accepted and settled other Maori lake claims by negotiation in the 1920s, including Taupo and the Rotorua lakes, but persisted in its Waikaremoana appeal.

The Tribunal says justice delayed was justice denied, with the Crown's delays effectively denying Maori access to the courts.

In addition, the Tribunal found the Crown failed to provide for legal recognition of the people's relationship with their taonga the lake, through a community title.

Instead, the Land Court individualised the title to the lakebed.

The Crown also acted in what is described in the report as an unprincipled and unfair manner after the decision of the Maori Appellate Court went against it in 1944; it continued to deny Maori ownership for a further 10 years.

And in a move that took the battle for ownership of the lake beyond the courtroom, the Crown was found to have breached the Treaty in 1946 when it modified and permanently lowered Lake Waikaremoana without consulting the lake's guardians or compensating them for the immense damage to their taonga.

The Lake Waikaremoana claims were lodged by Tuhoe, Ngati Ruapani, Ngati Kahungunu, Ngai Tamaterangi, and various associated groups and individuals.

The full report is available from 9am on the Waitangi Tribunal website.