-"Serious" incidents included physical harm requiring medical treatments, threats made with an intention to harm, stalking or intimidation of staff.
-"Moderate" incidents included assaults where there was no injury, aggression and abuse.
-"Minor" incidents were all other incidents that impacted the safety of staff and clients, or impacted the physical security of ministry assets, information or data.
Work and Income deputy chief executive Dorothy Adams said every threat was taken seriously and dealt with swiftly by ministry staff and police.
"It is unacceptable for people to threaten ministry staff who are carrying out their professional duties," she said.
"On September 1, 2014, the ministry introduced a zero tolerance policy towards abusive and violent behaviour against staff.
"The implementation of this policy resulted in an increase in reported incidents in 2014."
WorkSafe filed a charge against the Ministry of Social Development following the Ashburton shootings.
Following the tragic incident at Work and Income in Ashburton, the ministry commissioned an independent security review by Deloitte New Zealand. The ministry added more than 250 additional security staff to sites, and put in new security processes, including controlled access at all Work and Income sites.
Each site had at least two security guards who could ask people to provide proof of identity and decline access if they presented as a risk.
Nationally, there were more than 8000 security incidents at Work and Income sites in the past three years - about 10 every working day on average. More than 1300 of the incidents required police intervention.
Thirty one of the incidents were "critical", more than 850 were serious, almost 7000 were moderate and more than 700 were minor.
