The report showed in May (most recent figures available) there were 120 outstanding health and safety incident investigations. The DHB's target was to keep that number down to 10. Since the beginning of this year that figure has been slowly rising.

The number of staff injury claims has more than doubled from 29 in April to 64 in May.

Workplace violence and aggression was noted as one of the top three contributors to injury claims along with patient handling and physical environment.

An Auckland DHB spokesperson said the increase was a result of more staff reporting these incidents rather than a rise in violence.

"Auckland DHB has introduced a new safety management system to record incidents, including incidents of workplace violence and aggression.

"We have been actively encouraging reporting in this system and as a result, we are seeing an increase in the number of incidents recorded," the ADHB spokesperson said.

Powell said violence towards hospital staff was not isolated to Auckland.

"It's happening nationwide and the number of incidents we are hearing from our members is escalating. It's very bad."

Powell said a lot of the abuse was a result of drugs.

"There's a change in societal attitude. Hospitals as places of illness and caring are not being respected for their purpose."

She talked of her own experience when visiting her mother last month.

"There was a man walking up and down the corridor talking very aggressively. I asked if he could take it outside because it was disturbing people and he gave me a bit of verbal abuse before disappearing.

"The nurse thanked me for dealing with that because she said she couldn't."

Powell said hospitals needed to look at a zero tolerance policy for any physical or verbal abuse so people would be removed if it occurred.

She said these incidents were not just occurring in emergency departments but all the wards.

"I hate to say it, you know, but in the ED environment, maybe we're going to have to have policemen on site. It's sort of getting to that level."

Last week the Herald reported nurses in Middlemore's emergency department had been given personal safety alarms they could activate when in trouble.

Canterbury District Health Board's abuse rates against staff were particularly high.

In the first five months of 2018, CDHB recorded 388 incidents of physical assault towards staff from patients and visitors, and 247 incidents classified as verbal abuse.

Canterbury DHB chief people officer Michael Frampton said there had been an increasing number of assaults over the past four years and many were in specialist mental health services.

"This increase is the direct consequence of delivering care to a significantly greater number of people than our mental health facilities were designed to accommodate."

Frampton said the impacts of New Zealand's largest natural disaster continued to have a profound impact on parts of the Canterbury community.

"On any given day, we can be managing up to 90 acutely unwell mental health inpatients in our 64 bed inpatient facility. This is a really challenging environment for both patients and staff," Frampton said.

Bay of Plenty District Health Board recorded 103 incidents of "aggressive behaviour" by patients and visitors towards staff over the same period.

"Yes, workplace violence from patients and family members towards staff is an issue," BOPDHB's quality and patient safety manager/acting general counsel Debbie Brown said.

Counties Manukau District Health Board recorded 68 incidents of physical assault towards staff from January to May this year.

A CMDHB spokesperson said they accepted that employees across all its services do, at times, experience and report incidents of inappropriate behaviour by patients towards them.

"We actively encourage staff to report all types of incidents that occur, and to seek support in dealing with these, both at the time and if they feel this is affecting them subsequently," the spokesperson said.

In Whanganui, only six "aggressive behaviour" incidents towards staff by patients and visitors had been recorded this year.

But last month the head of the emergency department at Whanganui Hospital, Paul Delporto, said it was likely staff were too busy to file incident reports for everything, but where it was serious police would be called.

Whanganui District Health Board people and performance general manager Hentie Cilliers said they too were experiencing the rise in agression but not at the same rate as in other centres.

Cilliers said hospitals could be an extremely emotional setting which, from time-to-time, resulted in stressful situations escalating further than what was acceptable.

"Some patients are also experiencing health conditions, such as confusion or dementia, which may unknowingly impact their behaviour and result in unintended violence."

Acting Minister of Health Jenny Salesa said her expectation was that, as the employers of hospital staff, DHBs took steps to ensure their employees could get on with their work in safety.

"Any violence in the workplace is unacceptable, particularly when it is directed at hard-working and dedicated hospital staff."