Some meat companies are tightening conditions on the supply of ram lambs, saying the meat of older animals can taste tainted.
But Alliance Group does not rate it as a significant issue.
Affco and Silver Fern Farms have both announced dates after which they will not accept ram lambs, because the taste of older animals can be substandard.
In its latest newsletter, Affco said it preferred not to have ram lambs supplied after January 1 and that it was responding to "quality sensitive markets".
"The eating quality of such product is less than ideal and can be damaging to the industry."
Silver Fern Farms has announced it will only accept spring-born ram lambs up to March 31, after which they will be treated and paid for as mutton.
Chief executive Keith Cooper said the fact Silver Fern's date was later than Affco's reflected the later season in the South.
But Alliance chief executive Grant Cuff said feedback from markets indicated tainted ram lamb was not a problem until midwinter.
"We have no intention for the coming season of putting the same rule in place."