An anti-1080 group is threatening to bring down Department of Conservation helicopters if it drops the controversial pesticide in Taranaki's Egmont National Park.
The threat comes just a month after the group, called the New Zealand Hunters, illegally released dozens of sika deer into north Taranaki forests in what DOC believes is retaliation for dropping 1080.
In a letter sent to DOC and media organisations on Tuesday, the group has threatened to mount a war against the use of the pesticide.
"This will be a war like no other, you watch this happen around you," it reads.
"We the hunters of New Zealand have had enough of your bloody lies.