The Sheep Dog Trial Association has raised concerns about phasing out the use of dogs to herd livestock at meat processing plants.
The biggest processor, Silver Fern Farms, is aiming to minimise their use after a delegation from the British supermarket chain Tesco noted dogs at one plant acting aggressively towards the sheep.
The other large meat co-operative, Alliance, says it has phased out the use of dogs at half of its sites, and is designing stock-handling facilities so they are not needed.
Association president Merv King says it is safer and less expensive to use dogs, rather than people, to herd the sheep.
He says New Zealand sheep are accustomed to being mustered by dogs and the handling of stock at freezing works without dogs has not been "all that brilliant" in some cases.