Inspections of Otago dairy farms have shown the level of effluent pollution has more than halved on the previous two years.
The Otago Regional Council recently completed inspections on 95% of the region's 380 dairy farms.
There were eight cases where legal action would be recommended, compared to 21 last season and 26 the year before, director of resource management Selva Selvarajah said at a meeting of the compliance committee last week.
"It is very pleasing," he said.
However, it was concerning that six of those eight involved North Otago farms.
"It's a new emerging situation that all of a sudden North Otago farmers are non-compliant."
Of the six cases, four involved direct discharges to a waterway.
"It is hard to pin down the specific reason for the trend."
The large number of Southwest Otago dairy farms found to be non-compliant in previous seasons had "virtually gone", he said.
So far, only one of the cases possibly facing prosecution was from that area.
"It's still early days, but we have to accord credit to farmers who have made a lot of effort to comply."
Cr Bryan Scott said the council had been quick to criticise farmers in the past and while it was still early, it was "a great outcome".
Cr Stephen Woodhead said it was "very, very pleasing" to see the improvements as a "lot of time and money" had been invested by the council into assisting farmers.
"It's good to see the reflection of that in the results."
The inspections were due to be completed in the next few weeks.
