The Government is being accused of "legislation by stealth" following the release of a policy that would see teeth knocked out of local protection against genetically modified organisms (GMOs).
Northland councils are engaged in a court battle to shield their districts from the risks of GMOs.
But the proposed National Environment Standard on Plantation Forestry (NES-PF) would loosen restrictions on genetically modified pine trees and force councils to remove wording around GMO trees from their policies and plan changes.
Whangarei District Council, Far North District Council and Northland Regional Council are among those that have moved to use the Resource Management Act to put restrictions on the release of GMOs, further to those provided under the Hazardous Substances and New Organisms (HSNO) Act.
The NES-PF would see councils lose the right to use their Resource Management Act powers to restrict the planting of GE trees.
GE Free New Zealand president Claire Bleakley said the HSNO Act was insufficient on its own, as it required little accountability if the release of GMOs caused harm.
Ms Bleakley said it was impossible to know what GE pines could do to native ecosystems.
The proposed NES-PF was first released in 2010 and contained no GE tree provisions.
A Ministry of Primary Industries spokesman said that, following consultation with a working party, it was re-released in 2014 with a clause around GE trees. This was "not an afterthought," he said.
Whangarei District Council team leader of futures planning Kerry Grundy said the GMO provisions seemed to have come "all of a sudden".
"People are saying: why have you slipped this in? It's overriding what councils want to do. If we have provisions around GM pine trees - which we do at the moment - we will have to take them out," he said.
A recent Whangarei Environment Court ruling affirmed the right of councils to regulate GMOs, though the instigator of the case, Federated Farmers, is now appealing to the High Court, a move described as "extraordinary" by Ms Bleakley.
"It doesn't seem to have any rhyme or reason. All the work Whangarei has done over 15 years will be out the window," she said.
The proposed NES-PF would negate the Environment Court decision, she said.
"Actually, this is legislation by stealth."
Whangarei District Council group manager district living Paul Dell said the council had been involved with an inter-council working party around GMOs since 2004.
Since then it had spent about $50,000 on expert advice and legal fees on the GMO issue.