Three companies want to build massive dairy farms in the Mackenzie Basin, where cows would live in "cubicle" stables most of the time.

Opponents warn the plan will tarnish New Zealand's environmental reputation.

Proposals by the three companies for resource consents for 16 new dairy farm developments managing nearly 18,000 cows housed in cubicle stables are before Environment Canterbury (ECan).

Under the plans, cows will be confined in cubicle stables 24 hours a day for eight months of the year, from March to October, and allowed outside for 12 hours a day from November to February.

The Green Party says the applications for land around the southern end of Lake Ohau and near Omarama mark the dawn of a new age of dairy farming in New Zealand.

"We've seen the dairy intensification happening and now we're into industrial factory dairy farming, pure and simple," co-leader Russel Norman told The Press.

If the proposals went ahead, vast amounts of cow urine and faeces would be discharged on to land daily, threatening pristine high country lakes and rivers with pollution and algal blooms.

Using Environment Waikato data that cows produced 15 times more waste than humans, it would be "like building a city for 270,000 people in the Mackenzie Basin and having them crap on the ground", Norman said.

"They are applying for effluent storage ponds to store 400 million litres of effluent and want to release 1.7m litres of that to land a day."

Federated Farmers dairy chairman Lachlan McKenzie said cows being kept in cubicle stables was "not like pigs in a sow crate".

There were different designs but generally cows could sleep in their own cubicle and move into the stable or outside to feed and socialise.

The Mackenzie Country applications, which give environmental consultants Mitchell Partnerships in Dunedin as their address, have been made by:

Southdown Holdings, for six dairy farms with up to 7000 cows;

Five Rivers, for seven dairy farms with up to 7000 cows; and

Williamson Holdings, for three dairy farms with up to 3850 cows.

The first set of resource consent applications for water takes for irrigation are being heard now, and the second set for the effluent discharges are open for public submissions until December 18.

Norman said keeping cows in cubicle stable they did not leave for eight months was a "radical departure from our tradition of farming stock outside and on pasture".

It could do "immense harm to our clean, green international brand" and was extremely concerning from the animal welfare perspective.

"Fonterra counters food-miles arguments from European competitors by saying our milk products are more environmentally friendly than factory-farmed milk.

"This proposal flies in the face of that strategy.

"They are doing this, I presume, because it is cold and such inhospitable dairy country. But it is stupid – it is iconic brown-tussock country, extremely valuable to tourism. People do not travel around the world to look at factory farms."

Agriculture Minister David Carter said he wanted New Zealand's special landscapes to be maintained.

"I am concerned about the proliferation of dairying in fragile environments. They shouldn't be allowed to proceed unless we can be sure they can mitigate any adverse environment effects.

"On the other aspect, providing it adheres to acceptable animal welfare standards, I don't think there are issues there," Carter said.

McKenzie said it was "rubbish" of the Greens to suggest the cows would be confined to a cubicle, he said.

"It's a bit rich for the Greens because they are telling people that should have these sorts of homes for stock to keep them off pastures.

"You collect the nitrogen on concrete, put it into a bunker and then spread the nutrients very lightly across the paddock so the grass can fully utilise it so you don't have the leachate into a normal grazing situation. From an environmental point of view they are trying to do the right thing."

- The Press