The report modelled that a 350-sow farm would need to save its existing cash earnings for 19 years - just to cover the costs required under the proposed changes.
Taranaki pig farmer Karl Stanley said investing in the necessary infrastructure for his farm would cost well over $3 million.
"We're talking having to increase the shed numbers, which would be a substantial amount of capital expenditure," he said.
Stanley's Taranaki farm is a 400-sow unit that he said produces 11,500-12,000 pigs per annum.
"The big question that needs to be asked is, how are we going to pay for this?" he said.
"Because at the moment, New Zealand-raised pork is competing with imported pork that's not following the same standard as we are, and it's also coming in at a much cheaper rate, which is holding New Zealand pork back at a rate we have to compete with."
Stanley said that backed pork farmers into a corner.
"We're in a big fight to try and stay economically viable and if these new codes come into place, we're going to see major costs put on top of use, without being able to get any gains."
Stanley said the changes could price farmers out of the market, as he had little faith consumers would swallow the 18.8 per cent price hike at the supermarket for New Zealand pork when imported meat was cheaper.
"We won't be able to raise their price, because, in the grand scheme of it, all New Zealand consumers are seeing is price, and if we're pricing at almost 19 per cent higher just to try and get our costs back, we won't be able to sell our product.
"The simple fact that we need is a level playing field and imported pork needs to follow the same standards that we do.
"The last thing I want to see is New Zealand having to rely on foreign pork to feed the country because if the changes do go through, it will decimate the entire pork industry.
"It won't just be a small portion of us it will be a very, very big portion of us that will just become non-existent."
Stanley said some farmers would have to take out a bank loan to cover the costs of the proposed changes - but they can be hard to come by due to uncertainty in the market.
"Banks need to be comfortable lending to an industry that is viable and sustainable," he said.
"If we're having to compete with imports coming into the country, then if we went to the bank, can we get a loan to make these changes?
"They'll probably be asking if it's wise, if it's economically valuable to them and to ourselves because I know that they have an interest in our farm, to make sure that we're not making silly decisions."
"It's going to be a very challenging, challenging time."
He said money that had been put aside for green initiatives such as a biomass boiler on the farm will instead go towards the welfare changes if they go ahead.
Consultation on the proposed changes close on July 8.
- RNZ
