The latest assessment of the Dairying & Clean Streams Accord is due on Thursday from the Ministry of Agriculture.
It is expected to show more than one in 10 dairy farms are significantly in breach of cowshed effluent disposal rules, and show farmers falling short of targets agreed between Fonterra, regional councils and the Government.
The accord was signed six years ago.
Fonterra has now imposed fines on polluting farmers of up to $3000 from next year.
Fonterra itself has been penalised by $25,000 by the Environment Court for a discharge into the Tasman Sea from the Whareroa dairy factory near Hawera in November 2005.
About 5.5km of coastline was coated in cream, up to 10cm deep.
Another incident last November, in which an estimated 20,000 litres of cream was discharged, but did not wash ashore, resulted in an explanatory letter from the company.
Another spillage of 10,000 litres five days later drew a $750 penalty.