The country's largest paper mill is applying to extend permits to discharge effluent into the Tarawera River for 35 more years.
Carter Holt Harvey and Norske Skog want to continue discharging up to 275 million litres a day of poisonous water from the Tasman Pulp and Paper Mill for the next 35 years.
Opponents say it's ruining the local environment and must be stopped.
Independent commissioners began hearing submissions against the proposal at the Bay of Plenty Regional Council on Monday.
A grower of organic kiwifruit in Te Teko, Harry Lagocki, said water quality is becoming increasingly important for food producers in order to be able to sell goods into overseas markets. He said New Zealand has a lot to lose if it allows pollution, including the world-class status of the country's dairy herd.
Mr Lagocki said he does not feel the community will accept the permit extension because that flies in the face of the image New Zealand wants to project of itself as clean and green.