The Waikato Regional Council is undermining efforts to improve water quality by ignoring its own policies, a water quality activist says.
Matamata man Angus Robson, a heavy machinary engineer who advocates for water quality in the region, said large dairy conversions in southern Waikato - managed by the State-owned enterprise Landcorp - would significantly degrade the region's waterways by increased nitrate leaching.
The council had policies in place to protect and improve water ways, including the Resource Management Act and its vision and strategy, but he believed the council was ignoring them.
"By allowing a large-scale conversion of a pine to pasture area, you are not maintaining and improving water quality, in fact you're doing the opposite, and you are actually allowing contaminants to land in the water.
"The fact is they've got the policies, these have been hard fought, often they've taken a long time to develop, they're built around some very good advice and working together with people, and then they're just ignored."
Mr Robson said if the Waikato Regional Council was serious about cleaning up its rivers and lakes, it must do more to stop further dairy conversions in the region.
But he said a moratorium on dairy conversions in the Waikato, which the Green Party was calling for, might not be the answer.
"It's difficult to have a moratorium on conversions when internally it's intensification causing many of the problems.
"What I would prefer to see is a quick move to nutrient limits, catchment wide, and then by being forced to adhere to nutrient limits, the conversions and intensification would take care of itself."
A Waikato Regional Council spokesperson said it had a wide range of policies, projects and programmes in place to address water quality issues, and it was completing detailed work looking at forestry-to-farming-conversions in the southern Waikato.
But the council also said it did not have the power or means to impose a moratorium within a timeframe that would make any meaningful difference.