A female frontline staff member has been hospitalised after being attacked inside a Christchurch Work and Income branch, prompting a review of security systems.
The Ministry of Social Development, which oversees Winz, and the Public Service Association are investigating how the alleged attacker circumvented security measures on Friday morning at the Sydenham branch.
There are a minimum of two security guards on duty at Winz offices with public access, and up to four on shift at busy sites.
Workplace protection at Winz was reassessed after Leigh Cleveland and Peggy Noble were shot dead by Russell John Tully inside the Ashburton branch in 2014.
The Sydenham branch on Durham St also had an "airlock" door where visitors can be screened after entering the front door.
The Winz office in Sydenham was locked down after the staff member was attacked on Friday. (Photo / Geoff Sloan)
It was initially feared the woman, who was working on reception, had been stabbed but police confirmed no weapon was involved. She was being treated at Christchurch Hospital.
An 18-year-old woman was subdued by security, then arrested and charged with injuring with intent to injure and wilful trespass.
She is scheduled to appear in court on Monday.
Christchurch-based PSA lead organiser Anthony Rimell described the attack as "a serious harm event", and sadly indicative of the threats staff confront on a regular basis.
"There's been an increasing number of violent incidents at MSD buildings in Canterbury.
"A number of clients have certainly chosen to issue verbal threats against staff, they've also chosen to take out their frustrations on doors and furniture," he said.
The union in conjunction with MSD is providing practical and emotional support for the victim while assessing security measures is another priority.
"We'll be looking to identify what happened, whether the current safety protocols were in some way breached," Rimell said.
"The bigger question is: Are there ways to make the workplace safer? What can be learned from this to minimise the risk of this sort of thing happening again?
"There were a number of enhancements put in place (after Ashburton) but our view is with health and safety you can always improve."
The Winz building, which also accommodates Oranga Tamariki, was locked down after the incident and reopened on Monday, when staff received counselling. (Photo / Geoff Sloan)
The Sydenham Winz building, which also accommodates Oranga Tamariki, was locked down after the incident and re-opened on Monday, when staff were counselled.
"It's an ongoing concern," Rimell said.
"There's always a risk with an angry and upset client that the situation can escalate to something more.
"It's not acceptable, however someone is feeling, for a public servant to be attacked in the course of their job."
MSD regional commissioner for Canterbury, Diane McDermott, said the staff member was recovering well.
"We have put a range of supports in place," she said.
"We put our people's wellbeing first and have a zero tolerance for aggression or abuse towards our staff, contractors, clients and the public."