They walked with vegetables and placards in their hands, and passion in their hearts, to Shadow Minister for Agriculture Joel Fitzgibbon's office on Monday.

It was their way of voicing their opposition to the federal government's decision to remove the checks and balances that had been in place when it came to assessing Genetically Modified Organisms.

That decision has opened the door to new techniques like CRISPR and SDN-1, which Slow Food Hunter Valley's Amorelle Dempster said went beyond species specific gene editing and required proper regulation.

"Soon we won't know if it's GMO when we buy our food," she said.

"People in the street kept saying to us 'how did this happen?' and 'why haven't we been told about this?'. People feel like they have been left in the dark about this and they want to have the choice."

The protesters, led by Ms Dempster, have found allies in the Greens Party which will put forward a disallowance motion in the federal Senate on November 13 to try to reverse the government's changes.

It will need the support of the crossbench and the Labor Party.

"We want to feed our families, so how will we know that the food is healthy and safe in the future if this motion is defeated?," Ms Dempster said.

"The shadow minister wasn't in his office, but we are calling on him to do the right thing for the future of our food to make sure that it is safe and clean and Genetically Modified Organisms are regulated so there are some checks and balances before it is unleashed on our shelves."

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Slow Food Australia has joined the fight and started a petition on the issue.

Ms Dempster said farmers, especially those who grew organic food, would also be affected.

"The seed companies take the best of our produce and make modifications to them and then they own the patent on the seeds. Farmers will no longer be able to own their seeds, or replant Genetically Modified seeds that they have bought, or be guaranteed that their seeds aren't affected by any modification," she said.