Farmers told Otago Regional Council on Monday that new water quality rules are unfair and unaffordable.
The council has started five weeks of public hearings on a plan change called 6A.
The council received more than 400 submissions on the change, which aims to give land owners more power and responsibility for the quality of the water running into Otago streams, rivers and lakes.
But Middlemarch sheep and beef farmer Kate Wilson said the change will mean she will have to bar anglers and hunters from the farm, because of the risk they could pollute waterways.
She said she agrees with the intentions of the change, but not way it's being done.
Ms Wilson said she will be unfairly responsible for all water discharges on her land and she can't guarantee that enforcement personnel would be very practical.
Otago University water scientist Marc Schallenberg told the hearing that the new rules are a dangerous mistake.
Dr Schallenberg says Otago's approach of tracking nutrients once they are already in rivers and lakes is dangerous, and likely to be a step in the wrong direction.