The Department of Conservation (DoC) says it's "deplorable" that staff have faced death threats and property has been damaged as tensions over 1080 escalate in the South Island.
DoC says it has referred around 20 separate incidents to the police, ranging from vandalism to threats to helicopter pilots and its own staff.
Protesters have been trying to disrupt DoC's aerial drops of the poison on the West Coast and in Fiordland.
Eyewitnesses claim pellets have been dropped in public areas but DoC says that's not the case, and it's concerned for its staff.
"We've certainly had cases of people turning up at homes in the middle of the night, of damaged property," says DoC director general Lou Sanson.
"We've had threats to follow people home, we've had threats that 'we know where your children are'."
Mr Sanson says some threats are being posted on social media and DoC is taking the matter seriously.