They're relying on social media to spread their message - and it's quickly going viral.
Pure Hawke's Bay President Bruno Chambers says: "We've been really pleased at the level of engagement to date."
"I think it's really sending a very clear message to the Māori party, and the other parties, that 360D is not wanted in the regions."
The Maori party is the only party which supports National's law.
Environment Minister Dr Nick Smith says GMOs are best regulated nationally because councils have no biosecurity controls between districts and lack appropriate expertise.
But Hastings District councillor Henare O'Keefe says the community knows what's best for their region.
Before Christmas, the Māori party sent a letter to the Minister saying they don't support changes that may interfere with GM Free zones.
Hastings was the first district to declare their GM Free status, the Far North, Whangarei and Auckland followed and the four are fighting back against clause 360D in the RMA bill.
Mr Chambers says being able to call Hawke's Bay GM Free is a huge benefit to the region.
"We can see no economic upside by embracing GM technology at this stage."
The Environment Minister says Anti-GM campaigners are wrong to claim the Resource Management Act changes before Parliament will change the way Genetically Modified Organisms are regulated.
"The EPA has taken a very cautious approach to the approval of GMOs and has approved only two for release in 25 years - one for a vaccine for equine flu and last year a GMO treatment for liver cancer. This experience and examples reinforce there is no need for councils to duplicate the work of the EPA in GMO regulation," the Minister says.
"It is very important for New Zealand to maintain and enhance our reputation for safe, good quality and sustainably produced food. This is best achieved by ensuring our marketing claims have integrity and are science based. There is no scientific basis for any region of New Zealand claiming they are any different in respect of the presence of GMOs than any others."
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