A conservation group is warning irrigation plans for the Mackenzie Basin could change its unique landscape and cause an "environmental disaster".
About 35 companies and individuals have lodged applications with Environment Canterbury to irrigate about 27,000ha in the Mackenzie Basin.
Forest and Bird South Island conservation manager Chris Todd said the proposed irrigation to allow intensive farming of the basin could turn its "spectacular dry, sunburnt vistas" into a replica of the highly developed Canterbury Plains.
"Industrial-scale farming in our most fragile and visually stunning high country landscapes is not sustainable."
Under the proposal, 56 threatened species of plants would be put at further risk; Lakes Tekapo, Pukaki, Ohau and Benmore could be affected by farm-nutrient runoff; the multibillion-dollar high country tourism industry would be adversely affected and extensive wetlands destroyed, he said.
"The Government needs to step in and prevent an environmental disaster," Mr Todd said.
Mackenzie Irrigation Company director Murray Valentine, of Dunedin, said compared with the size of the Mackenzie Basin, the 27,000ha that farmers wanted to irrigate was very small.
The plan was not to irrigate the high country but the "flat land", he said.
If farmers got approval, they could increase stock rates per hectare by up to 15 times.
"We're talking about areas that are basically the nearest thing we have to desert and are completely modified with hieracium and wilding pines."
Landscape would be a big issue at the hearings and no-one wanted to see it destroyed, he said.
Farmers were aware there were areas of tussock land that needed to be protected and the hearing would give both parties a chance to air their views, Mr Valentine said.
