There have been 111 reported incidents threats, harassment, intimidation and assault against DOC employees in the past 11 years.

In mid-October, a member of the public walked into a DOC office, confronted the local manager and threatened to kill him and his family.

It's not the first death threat a DOC employee has received. Earlier in December, a letter threatened to shoot down DOC helicopters and to wage "war" against the department.

In June and September, wheel nuts on DOC vehicles were loosened - tampering with potentially deadly consequences.

The department's records of threat, harassment, intimidation or assault go back to 2006, which had only one reported incident - an assault. As of early December, 2017 has had more than 30 incidents alone.

READ MORE:

* Department of Conservation calls in police

* Letter 'declares war' on Department of Conservation

* Police called after DOC staff and families threatened

In 2007, a string of gun-related incidents occurred. Shots were fired near DOC employees on four occasions.

In one, a ranger was driving between work sites in a DOC vehicle when a bullet hit the car below the passenger door wing mirror, shattering the window.

A more recent example is from 2014, when a DOC office worker received a call from someone who said they "wanted to go down there (to the DOC office) to blow someone's head off". The caller then hung up.

Staff have been assaulted, abused and harassed. They've been on the receiving end of road rage. They've been targeted on social media.

JEREMY WILKINSON/STUFF A large number of the incidents occurred in relation to 1080.

They are just some of the 111 reported incidents against DOC employees in the past 11 years.

DOC said reporting of incidents has improved during that time. It also said it's important to remember the department has about 1000 front line staff and rangers who "interact with New Zealanders every day".

Almost a third of all reported incidents were related to 1080. In total, over the 11-year period, 44 incidents were then reported to police, DOC said.

DOC's Director of Health and Safety, Harry Maher, said besides improved reporting, the increase of incidents could be because the department was doing more predator control work than before.

"Particularly with the launch of 'Battle for our Birds' in 2014, along with issuing more public information. DOC is seeking to be as open and transparent as possible about the use of aerial 1080, when the control is happening and when there are scientific findings.

"This may have led to the more intense interest in DOC's use of aerial 1080 than in the past."

Maher said DOC "abhorred" any form of threat, harassment or confrontation of staff members or contractors.

"DOC workers are dedicated to the protection of our native birds and wildlife, and the special places where those creatures live. It is unacceptable that they should have to manage these types of threats in their day to day work," Maher said.

"Although threats can be upsetting and disruptive, staff are professional and rally behind each other to offer support. It is comforting that the Department's senior leadership and the State Services Commission are taking threats against staff so seriously."

Threats and similar behaviour was not ony disruptive for staff, but also their family and DOC in general, he said.

Staff had been given a "confrontation guide" to help them deal with harassment and confrontational behaviour. Affected staff were offered support and counselling.