Food producers are not expecting an immediate income boost after the Hastings District Council became the first local body in New Zealand to block genetically modified food production, a move the Environment Minister called unenforceable.
"A key thing for us is to hold our status quo," grower Scott Lawson said.
The exporter and member of lobby group Pure Hawke's Bay said the organisation wished to prevent any genetically modified organism (GMO) field trials or crops.
"The best-case scenario is it gives us a lift in market premiums versus our international competitors, which may be having issues with GMO contamination.
"It will reinforce our clean, green international image, which is what our customers are wanting."
The region had a century-long record of food production "and we just want to maintain that premium brand".
"We want to look after all that good work that went before us and make sure we don't erode any of those market premiums and perceptions that our customers have in the future because perception is reality in that international market place."
Hastings Mayor Lawrence Yule said the council ruling was "very powerful" for growers, enabling a 10-year GMO-free guarantee - the life of the District Plan.
"We are the food bowl of Australasia - we produce some of the best food in the world and we need to do everything we can to enhance its value for growers," he said.
The council would liaise with other councils to widen the GMO-free area but should amalgamation eventuate, a new District Plan would be needed, requiring consultation with the widened community.
Environment Minister Nick Smith said he would not challenge the GMO policy but called it "gimmickry".
"The only practical way New Zealand can regulate new organisms - like a new seed, a new insect or new vaccine - is nationally, because once it is in one district it can easily spread by persons, a vehicle or wind to other areas," he said.
The Environmental Protection Authority (EPA) had a robust system for regulating GMOs nationally and the only one approved was an equine flu vaccine.
"We have a further application currently around a medical therapy for liver cancer, which is a genetically modified vaccine virus. It requires both a Medsafe approval as well as an approval from the EPA. It would not be sensible to have every council in New Zealand, as well as those two agencies, making a decision whether the people in their community with liver cancer would be able to receive it."
He supported marketing areas like the Bay as "clean, green and natural" but claims needed to be scientifically correct and practically enforced.
"Unless we are going to set up bio-security inspectors on the boundaries between every one of our councils then it is unworkable."
Crown Research Institute Plant and Food, which has a Havelock North facility, said it had no plans to field-test genetically modified plants.