Retiring MP and dairy farmer Mark Cameron is blasting the Green Party for proposing to ban the use of synthetic fertiliser and cutting cow numbers.
Cameron describes the Greens' policy as "completely out of touch with reality".
"Synthetic fertiliser has lifted millions out of poverty around the world over the last 50 or 60 years of its use," he told Dairy News.
"It has increased food production several-fold giving the farmers the necessary tools they need to be productive.
"The Greens' policy is a utopia that simply does not exist. Many countries have natural resources. Our greatest one is our ability to convert green grass into animal protein."
The Greens released their 'Drink Swim Fish' policy ahead of the upcoming election.
The party wants to tackle pollution before it reaches waterways. It proposes to phase out synthetic nitrogen fertiliser and take action to reduce stocking rates on a catchment basis to improve the health of rivers and drinking water quality.
But Cameron, who is retiring on health grounds after serving two terms as an ACT MP, says the Greens' policy would be a disaster for New Zealand.
"It will destroy property rights and productivity and production, ultimately making us a poor nation."
Another ACT MP, Andrew Hoggard, who milks cows in Manawatu, says farmers don't use fertiliser for "giggles".
"It's bloody expensive, but also veery important for growing crops and food."
Hoggard says less fertiliser means less production.
"If you reduce the supply of food, then the price will go up so, I'm not sure that's a brilliant idea for improving the cost of living."
Hoggard says reducing ag exports out of the country will slash export receipts.
"Farmers up and down the country are doing great work on protecting waterways.
"The way forward isn't one-size-fits-all, neither is more blunt rules from Wellington.
"But each farmer understanding the key risks on their farm, having mitigations in place, working with their neighbours on catchment plans.
"That's how we move forward and unlock our nation's potential," he says.