Federated Farmers is ploughing ahead with its court challenge to Hastings District Council's GM-free status, despite a string of failed attempts to stop other councils doing same.
The council was the first local authority in the country to ban genetically modified crops and animals under its 2015 district plan, prompting Federated Farmers to immediately challenge the rule in the Environment Court.
Auckland and the Far North have also since declared their regions to be GM-free and attempts by Federated Farmers to challenge them have been lost in the courts.
In 2016, the High Court upheld Northland Regional Council's right to decide whether to allow genetically-modified organisms in their region.
The farmers' lobby group appealed the decision, but lost, arguing the Hazardous Substances and New Organisms Act, not the RMA, was the overarching legislation that governed GMO use.
Federated Farmers tried to overturn that ruling in the Court of Appeal in February 2017 but withdrew its case in November, just weeks before a scheduled hearing, citing changes to the RMA would have reduced their chances of winning.
It was now challenging the specific rule in Hastings' district plan that prohibited GMOs from being released into the environment.
Rule 29.1 forbid any release or field testing of any genetically modified organism, even if it already been approved by the Environmental Protection Agency.
GMOs being used in labs or for medical use, such as in vaccines, were allowed.
Federated Farmers national president Katie Milne said the legal challenge was not about the "rights and wrongs of GMOs".
"GMOs are managed within a national framework, and local authorities such as the Hastings District Council (and communities within local authorities) have a role within that framework. The framework is set up under the Hazardous Substances and New Organisms Act, not the Resource Management Act.
"Federated Farmers' challenge to the Council in the Environment Court is about the Council attempting to pre-empt the national framework."
Hastings District Council was being supported by the GM-free lobby group Pure Hawke's Bay which represented local farmers, growers and exporters.
The council submitted its evidence to the Environment Court last week and Federated Farmers had until this week to respond before a hearing date was set.