A Department of Conservation (DOC) paper which found a Hawke's Bay dam could make the Tukituki River toxic shows public servants are withholding information about the project, Ngati Kahungunu says.
The draft - obtained by Radio New Zealand News, and which reveals the scheme could kill threatened fish species - was written for the Board of Inquiry into the Ruataniwha Dam but was not submitted.
Instead, DOC submitted a brief document which does not raise concerns about what could happen to water quality and the dangers for at-risk fish species in the Tukituki and Waipawa Rivers and tributaries.
Runanga o Ngati Kahungunu chair Ngahiwi Tomoana said it confirmed the tribe's suspicions that only selected information is being fed to the people.
He called it an indictment on the Government and the Hawke's Bay Regional Council, which wants to push forward with the Ruataniwha water storage project.
Meanwhile Conservation Minister Nick Smith has said he gave no indication to DOC about what they should include in its submission.
A Cabinet paper released to Radio New Zealand News under the Official Information Act says the Hawke's Bay process is guiding water management planning in other areas of New Zealand and the process may be used as a prototype for other areas of the country.