The Department of Conservation has spent more than $1 million protecting its staff from threats and abuse from anti-1080 protesters but says that doesn't reflect the full cost of what they're dealing with.
Incidents over the past 18 months include threats to shoot down DOC helicopters and skin the faces off staff.
A letter was delivered to DOC's New Plymouth office with a blue substance leaking out of it, and in the South Island a DOC worker's details were published online, with comments about filling him with lead, and needing good snipers in New Zealand.
The Prime Minister, Conservation Minister and Agriculture Minister have all become targets.
Over the past two years DOC has spent around $780,000 on security for aerial 1080 drops.
During October and November it spent another $295,000 on a Co-ordinated Incident Management (CIM) plan in response to an increase in threats and abuse, which culminated in an anti-1080 hikoi to Parliament.
That CIM involved covering the costs for up to 30 DOC staff to monitor the situation.
DOC spokesperson Nic John said they had been working with police to manage the situation - that had resulted in four warnings, four arrests and one conviction so far.
"These figures don't capture the true cost of security to the organisation. Other costs incurred locally have not been captured, as they are very hard to collate nationally."
He said it was unfortunate money was being spent on security, when staff were operating legally and in the interests of promoting conservation for all New Zealanders.
"I don't think that anybody should be subjected to the harassment and threats that our staff have - not many workplaces would tolerate this and we've done so for far too long."
Forest and Bird's chief executive Kevin Hague said it was infuriating DOC had had to shift money away from conservation.
"This is money that should have been available for the vital task of protecting our nature and to have it diverted, in order that DOC staff and contractors can be safe from these awful people, is just absolutely frustrating."
He said the irrational behaviour of the anti-1080 protesters was highlighted last week when autopsy results revealed a Weka, which was used during a protest, had likely been shot with a .22 rifle - despite claims it had died from 1080.
"These extremist anti-1080 protesters are just completely beyond reason, they don't use actual evidence in anything they say and their arguments are immune to the rules of logic that most people would apply," Mr Hague said.
Roger Lorigan runs the pest control company Epro, which carries out 1080 drops.
He said his staff had been the target of many threats and vandalism - including one incident in Northland where people had broken into his equipment and let 2000 litres of helicopter fuel out into the native bush.
"It caused quite a bit of environmental damage, plus they cut the helicopter buckets, damaged the trucks, there was about $50,000 to $60,000 worth of damage on that night."
Mr Lorigan said anti-1080 sentiment had ramped up over the past 18 months - but he remained committed to the cause.
"I've been dealing with 1080 for a long time and I'm a mad-keen hunter as well so I sort of see it from both sides.
"When you look at New Zealand's threatened species, and you look at its bush, it's a pretty spectacular thing to try and save - 1080 works, there's no ifs, buts or maybes and it doesn't do all the damage people try and say it does," Mr Lorigan said.