Ngāi Tahu is rejecting National's claim that it will take over 50 percent ownership of water assets in the South Island.
National Party leader Judith Collins said in a media release today that the government plans to reform the South Island's publicly owned water assets.
As part of the reforms, mayors have been told about a proposal for a single South Island water authority, she said. It would take over assets previously owned by towns and cities.
She said the mayors are outraged because the assets have been paid for by ratepayers over the years and Labour has not discussed the issue with New Zealanders.
Collins said it is concerning that the government is undertaking a radical interpretation of the Treaty of Waitangi that involves a co-governance system for many public issues.
However, the claim has been denied by the chair of Te Kura Taka Pini, the Ngāi Tahu freshwater group, Dr Te Maire Tau, who has accused Collins of "seeking headlines".
He said in a statement that Ngāi Tahu believed the water infrastructure asset must remain in public ownership.
"The tribe has been discussing co-governance of what will be publicly owned assets.
"Our goal is to ensure greater community representation, better environmental and health outcomes, and to safeguard against future privatisation.
"Ngāi Tahu wants to design the structure of the new entity with the Crown and share governance responsibilities."
This would be a safeguard against any attempts by future governments to privatise water assets that are being transferred from councils.
He said it did not want to own any three-waters infrastructure. "We want an entity that provides local solutions and ensures all communities have equitable access to safe and resilient three-waters services," Dr Tau said.
He added that both Labour and National governments, including one in which Collins was a senior minister, have sold public infrastructure, including electricity networks and rail, to overseas interests.
Ngāi Tahu has been in discussions with the Crown on the possibility of designing one of the new three-waters delivery entities that are being established under the government's reform programme to replace the 67 local councils currently delivering three-waters services.
"Our proposal, which we have consulted all the relevant councils about, explicitly does not include Ngāi Tahu ownership. The assets of the new entity would be owned by the communities who paid for them in the first place.
"If Judith Collins had bothered to ask Ngāi Tahu about this proposal, instead of seeking headlines, she would have had the correct facts sooner," Dr Tau said.