The Waikato Regional Council is considering laying criminal charges against a dairy farmer in the Waiuku district after finding effluent on the property being pumped into a tributary of the Waikato River.
The council's investigations and complaints manager, Patrick Lynch, says staff responded to a complaint from a member of the public on Tuesday and visited the farm.
Mr Lynch says they found several unlawful discharges of dairy effluent, including what the council considers a deliberate discharge into the environment, from a pump set up to channel effluent into a nearby watercourse.
He says the council regularly comes across illegal discharges which are the result of negligence or carelessness, but the latest one is "appalling".
The farmer has been given a clear instruction to immediately stop what he has been doing.