The South Island iwi is one of 190 submitters opposed to the district council's application to discharge wastewater overflows to lakes, rivers and creeks, or on to land in circumstances where it may enter them, for a 35-year term.
A further two submissions are in support, and one is neutral.
In its submission, the iwi said the discharge of human wastewater into the water ''is offensive to the values of Ngai Tahu''.
''The degradation of the cultural health of waterways as a result of discharges is a significant issue for Ngai Tahu.''
It was also concerned about a lack of feedback received during consultation with mana whenua being included or addressed in the application.
''It seems that the assessment of effects has concluded simply that because the application was discussed with mana whenua that cultural effects have been addressed.''
Other heavy-hitters opposed to the application include the Department of Conservation (Doc), Federated Farmers and the Central Otago District Council.
Doc director-general Lou Sanson said he wanted to see more commitment from the council to reduce emergency discharge events.
''While it is recognised the overflow events are unpredictable, the current application provides no maximums for discharge volumes, the duration of the discharge and how often this could occur.''
Mr Sanson also said the 35-year term was not suitable, and he wanted a 10-year term instead.
Federated Farmers hit out at the perceived double standards when it came to water quality.
''Our members are concerned about the disparity between how urban and rural wastewater is treated, with there being a noticeable leniency towards urban discharges.''
It said everyone needed to do their bit to improve water quality.
''Farmers have been spending considerable sums of money investing in high-tech wastewater treatment systems to reduce the chances of failures at their end.
''It is accepted that discharging untreated animal effluent into waterways is unacceptable - so should it be for territorial authorities and human waste.''
