A stream running green with dairy effluent from two separate sources on the same Otorohanga dairy farm has appalled Waikato Regional Council officers.
"The council is particularly concerned that one of the discharges to the stream appears to have been ongoing and deliberate," said investigations manager Patrick Lynch.
The contamination was found in the stream west of Otorohanga on Friday after a tip-off from a member of the public.
"We do not usually report this kind of incident until after it has been through a court process," said Mr Lynch.
"However, what we found on this occasion is of real concern. We have many farmers doing the right thing by the environment in our region but unfortunately there are still some in the sector who, quite simply, don't seem to care."