Seven Waikato farming entities have been convicted and fined a total of $303,700 for unlawfully discharging farm animal effluent into the environment.
The separate prosecutions were taken by Waikato Regional Council, and all related to pollution events in August and September 2018.
They were sentenced in District Court in the past two weeks.
Council investigations manager Patrick Lynch said the cases reflected the focused approach the council had taken to inspecting high-risk dairy farms.
"We are urging all farmers to have adequate effluent management infrastructure on their farm that can cope with various weather patterns and other on-farm work commitments.
"Unfortunately, these farms have had significant and avoidable unlawful discharges of effluent into the environment. Good infrastructure and vigilant day to day management can prevent this," he said.
The fines imposed ranged from $25,500 to $56,017.