"It's our view those arguments should be with the Environmental Protection Agency [EPA] and a blanket [GM] ban is a blunt tool which is unhelpful and unuseful."
Dr Rolleston was one of 12 speakers at a regional forum on genetic modification held in Hastings yesterday.
It had been promoted by Pure Hawke's Bay, which lobbied the Hastings District Council to declare the district GM free with the possibility of the status being adopted by the whole region.
Pure Hawke's Bay believed the status would give the region a unique marketing point of difference to sell its produce to international markets.
Dr Rolleston said, however, that achieving approval from the Commerce Commission for a GM free title would be difficult.
"How is the council going to patrol its borders to make sure the district doesn't get contaminated by its neighbours?
"What infrastructure is needed to maintain this GM purity, what does the council know that the EPA doesn't?
"Councils also need to consider what the cost to ratepayers will be to become a regulatory agency for GM use."
Seeking a GM free status would open up the council to liability issues such as those sustained during the leaky homes debacle, he said.
Farmers needed "all the tools available" to advance their industry.
Dr Rolleston presented figures which suggested GM plants were grown across almost 30 countries in great quantities. But information supplied by one of the following speakers, Professor Jack Heinemann from the University of Canterbury, contradicted the numbers.
His figure showed GM plants were grown in only about five countries and majority of GM work was found in the US.
People asked how could farmers and the community form a balanced view on the GM debate when there was so much conflicting information.
Professor Heinemann, a genetic engineer and molecular biologist, said the public should look carefully at the source of information presented when it came to claims on the pros and cons of GM organisms.
He agreed it would be difficult for Hastings to head a GM free programme by itself but commended the community for taking "control of the decision yourself".
"I do believe farmers can make good decisions but I don't believe farmers have more rights to make the decision [on GM] than anyone else."
Professor Heinemann believed the GM issue should be "a local one" for the region's community to lead.
Hastings Council will complete its review of the district plan next year and it will include a decision on whether it should include a policy on GM.
Federated Farmers president Bruce Wills, who farms in Hawkes Bay, was part of the organisation's team which made the submission.
