More than 8000 people have signed a Green Party petition calling for the state-owned farming enterprise Landcorp to halt further development of dairy farms in the Waikato region.
Green Party water spokesperson Catherine Delahunty presented the petition to Parliament yesterday.
Landcorp, the country's largest farmer, was in the process of converting forestry land to dairy farms for 29,500 more cows in southern Waikato.
Ms Delahunty said people, including farmers in the Waikato region, were concerned the conversions and the increased number of cows would result in water quality deteriorating.
Landcorp chief executive Steven Carden said its farms and conversions were guided by and met water and nutrient limits managed by regional councils.
He said the conversions were closely monitored to ensure the environmental impact was minimal.
"More than 8,100 signatures from New Zealanders who are really worried about water quality - they want Government to stop Landcorp, a state owned enterprise, from converting forests that help protect the climate, into water ways that are turning pink with slime and algae down stream.
"We believe that Landcorp should do this now, because they're the biggest land owning farmer in the country and they should be the ones that lead the way in farming, not polluting our waterways with excess nitrogen."