Federated Farmers is rejecting claims plans for intensive dairying in Canterbury will lead to "factory farming."
Three companies have lodged consent applications with the Canterbury Regional Council to establish 16 new farms in the Mackenzie Basin housing almost 18,000 cows.
The plan has alarmed the Green Party, animal welfare groups and an ecologist, who believes it will be disastrous for the area.
The Green Party says the cows will be "factory farmed" - kept in indoor cubicle stables 24 hours a day for eight months of the year and 12 hours a day for the remaining four months.
Effluent would be stored in large constructed ponds and discharged on the land in summer.
The Greens and the SPCA say such practices will harm New Zealand's clean green farming image.
Welfare group Save Animals From Exploitation says indoor dairy farming will lead to
health problems for cows, including mastitis. It claims many cows farmed this way become lame from standing on hard ground and increased milk production leads to heavy udders and bowed legs.
SAFE spokesperson Hans Kriek says research overseas shows cows farmed this way suffer, with cows developing mastitis from unnaturally high milk production levels due to the concentrated feed they receive.
But Federated Farmers says this type of dairy farming cuts costs, is environmentally friendly and will not tarnish New Zealand's reputation.
President Don Nicolson says the move is partly due to rising costs and pressure from lobby groups over the environmental impact of farming. He says many other countries use this type of farming.
Dairy Farmers New Zealand spokesperson Lachlan McKenzie says though he has not seen the consent application, he assumes the cows would be kept outside if the weather was fine.
Mr McKenzie says they would simply have a free stall to sleep in, if they wished, and it is incorrect to associate high milk production with health conditions.
Federated Farmers says some Canterbury cows kept on pasture already produce 50 litres of milk per day and a calf every year and do not suffer from mastitis.
John Hellstrom, chairman of the National Animal Welfare Advisory Committee, says the Mackenzie Basin's cold climate means cows probably would be better indoors at times, but believes eight months of the year would be hard to justify.
Submissions to the regional council close on 18 December.
Disastrous plan, says ecologist
Landcare Research ecologist Bill Lee believes intensive farming would spell disaster for native plants and animals in the Mackenzie Basin and the change could lead to the extinction of some species.
The plans involve taking water from high country waterways for irrigation - a move applicants say will make the land more productive.
Mr Lee told Checkpoint such dryland systems have adapted to a lack of water and a low nutrient regime in the soil. But the planned wholesale conversion of land would obliterate existing native plants and animals.