The Department of Conservation has criticised a group of anti-1080 protesters who illegally released a herd of sika deer into North Taranaki conservation forests.
The release was allegedly in retaliation for DOC's use of 1080 in the region, and put local stock at risk of TB disease.
DOC's director-general Lou Sanson said the department rushed to the forest area after receiving an anonymous tip off about the deer.
Department hunters had so far destroyed five of the animals and department staff were working to track down the rest of the animals.
Sanson called the illegal release of the deer "selfish" "short-sighted".
"This is not about hunting, it's about sabotaging community conservation projects that are working towards Predator Free 2050," he said.
"I'm disgusted by this behavior."
The department's 'Battle for our Birds' programme involved a range of pest control methods on conservation land across New Zealand.
The Taranaki region was home to multiple operations, which had so far enabled the reintroduction of the Kokako bird after an absence of two decades.
It was also in DOC's interests to prevent new incursions of feral deer into the area, as they provided an ongoing threat to native forests and ecosystems.
Sanson said the incident was the second illegal act lashing out at DOC staff in a fortnight. A staff member's private vehicle had the back window deliberately broken last Thursday.
Both incidents were under police investigation. The offenders responsible for the release of the deer would face the full force of the law under the Wild Animal Control Act if caught.
"Lawful protest is fine but potentially putting people's lives at risk with irrational behaviour has to stop before someone is hurt."
Sanson was urging anyone with knowledge of the crime to contact DOC or police.