Auckland Council has already included similar provisions in its Unitary Plan; Whangarei District Council voted to notify a similar plan change yesterday.
The cost-benefit analysis due to be presented to councillors today questioned claims that GM crops increased productivity, giving evidence that similar or better gains could be achieved through breeding; and highlighted the potentially huge costs and loss of export markets, jobs and economic growth that would follow GMO contamination of the food supply chain.
"It is unlcear whether economic growth and employment would increase as a result of the plan change. However, it would ensure these were not reduced by GM contamination incidents," the authors said.
The report added that Northland producers could benefit from marketing opportunities provided by a GMO ban. While declaring an informal GM-Free Zone would be cheaper than a formal plan change, it would not be legally enforceable.
The plan change would be a relatively small one-off cost which could be shared with Whangarei.