Fonterra has been fined more than $170,000 for polluting the Rangitāiki River from its Edgecumbe plant.
On six different occasions, Fonterra disposed wastewater into the river.
The dairy giant pleaded guilty to all six charges relating to their wastewater irrigation system and overflows between September 2014 and April this year.
The Rangitāiki River is important to a number of iwi including Ngāti Awa, Ngāti Tūhoe, Ngāti Tūwharetoa, Ngāti Whare and Ngāti Manawa.