Sow crates will soon be gone from New Zealand pig farms, after a new pig welfare code was released by the Government banned their use.

The new code, brought on by mounting calls for reform in pig farming practices, will see the crates phased out by the end of 2015.

Agriculture Minister David Carter says the science and the sentiment show the ban was needed.

“The Government now has moved to satisfy the demands that consumers expressed to Government. The way that this will now work is consumers must be prepared, that they want to buy New Zealand pork.

"They’re going to have to probably pay a little more than imported pork but in doing that they are able to adequately demonstrate they’re buying pork produced under the best animal welfare standards in the world.”

Pork Industry Board chief executive Sam McIvor says some farmers will feel the pressure over the changes.

“Farmers are obviously concerned about the cost of this change. We’ve had an independent analysis that suggests it might be up to $20m and farmers are going to have to be recouped for that.

"Just how that is going to happen is unclear yet but it’s absolutely critical that farmers are able to remain viable and obviously we’re up against 700,000 kilos of imported pork.”

Chairman of the National Animal Welfare Committee John Hellstrom says the new code puts New Zealand as a world leader in pig welfare.

“Certainly New Zealand now would have one of the very highest standards, it would be up with the top two or three countries in terms of pig welfare.

"And in terms of practical pig welfare I think it would be world leading, because countries like Switzerland and Norway which have got high levels also have a lot of state subsidy.”

Around 40 per cent of pig farms still use sow stalls or crates.

The use of farrowing crates has also been restricted, but won’t be outlawed until a new method to protect piglets from being crushed is found.