Farmers are being warned not to sell on any farm-grown seeds, as the practice may breach patent laws.
The concerns relate to a category of seed known as farm-saved seed which farmers are allowed to harvest and use on their own property.
The Plant Breeding and Research Association, which represents plant breeders and those that hold intellectual property rights to agricultural seed, says the issue arises when the grower sells farm-saved seed to other farmers.
That means no royalties are paid to the developer who holds the proprietary rights.
The association's executive director Ann Harper, says there's anecdotal evidence that this sort of selling occurs quite frequently, and has been growing over the past few years.