Some Otago farmers say a regional council plan setting water quality limits on farm runoff is too prescriptive to be practical.
On Monday, Otago Regional Council began five weeks of public hearings on the plan change called 6A, which would give all landowners tighter limits and more responsibility for managing agricultural run-off.
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.
Some of the farmers fear that will swamp them with rules they may unknowingly breach.
Philip Wilson, who owns a dairy farm on the Taieri Plains, has spent more than $1 million on environmental improvements to the property.
He says some proposals in the plan are too specific to work in practice.
Earlier this month, Manawatu-Whanganui Regional Council received court approval for new water rules in the One Plan, which crack down on agricultural run-off polluting the region's waterways.
Farmers had been fighting the changes in the Environment Court for six years.