E tū is calling for more security at hospitals and further staff training following the assault of a security guard at Christchurch Hospital.
The guard is the fourth to be assaulted in New Zealand this year and took place in the hospital's Emergency Department on the Queen's Birthday public holiday.
The incident happened weeks after an earlier attack on a security guard took place at Waikato Hospital - both the Waikato and Canterbury District Health Boards contract security services to Allied Security.
Meanwhile, another two guards who were assaulted at Hillmorton and Christchurch Hospitals remain off work following their serious assaults.
Mat Danaher, E tū campaign lead, said the series of assaults highlights the current outsourcing of security services.
"The fact is Allied Security is the security provider at both Waikato and Canterbury DHBs, and I would hope these DHBs, and DHBs nationally, are taking a serious look at who provides their security, and whether the services are fit for purpose," he said.
"In the case of Allied, we don't believe that's the case and we've lost any confidence they're up to the job."
The security guard at Waikato Hospital was badly beaten with an oxygen cylinder while on duty and will be off work for at least three months.
"She's got no independence at the moment. She can't do anything ... She struggles to even make a coffee," her son Carl Harney told the Herald.
His 47-year-old mother, who doesn't want to be named, and three nurses were attacked by a male patient in the early hours of May 15.
Harney said guards were called to an attempted self-harm incident, but not that they were entering a potentially dangerous situation.
"Mum was told there was a (person threatening to self-harm) going up the stairwell in the Menzies Building. And it wasn't that - it was something violent."
The guard's family are speaking out on their mother's behalf because they say she can't because she and other security guards have been muzzled by their employer, Allied Security.
Danaher said many other district health boards in New Zealand employ their security guards in-house, something E tū strongly supports.
"Directly employed security seems to be the model to look at for DHBs," he said.
"Our hospitals are plagued by violence and all staff are affected, not just our security guard members.
"Hospital security needs a whole team approach, and the best way to do that is to make sure guards are part of the same team as other staff."