Two men have been given a warning by police after an activist group sent a letter out saying anyone involved in an upcoming 1080 drop is "committing an act of terrorism".
West Coast Area Commander, Inspector Mel Aitken says the men have been warned and there are no plans to lay charges.
She said police recognised the right to a lawful protest and freedom of expression, however to maintain public safety police will take action when threats are made.
"The 1080 programme is lawful and the belief that anybody associated with this is committing an act of terrorism is absolutely incorrect," Insp Mel Aitken said.
"While all people have the right to freedom of speech as well as peaceful protest, I wish to make it clear that threats made towards individuals or organisations that are involved in the 1080 programme will be treated seriously."
Hikoi of a Poisoned Nation posted a copy of the letter on Facebook.
The group says they gave the letter to regional council, the Department of Conservation and Vector Control Services.
"You and your employees have had every opportunity to do the right thing you have lied to New Zealand," the Facebook post reads.
The group says the impact of 1080 on native species has been covered up and downplayed harming locals and tourists.
"You have coerced successive governments into committing acts of terrorism by their actions and/or inactions now the game is up jump ship or go down with it it's up to you.
"We will now use the full weight of the laws soon to be initiated by Jacinda Ardern and those already in existence under the terrorism suppression act 2002 to lock up those responsible for this chemical warfare on the people of New Zealand.
"All citizens must take every measure to prevent these attacks."
A five-year study published last year showed 1080 poison was behind a native bird boom, and it's also been credited with wiping populations of rats and other pests.
Anti-1080 protesters have ramped up their opposition in recent years, including loosening wheel nuts on cars belonging to Department of Conservation workers and threatening to "take down" helicopters.
A man who threatened to poison baby formula with 1080 was jailed in 2016.