The accusations sent to the Bay of Plenty Times, along with the leaked internal emails from staff to management at Tauranga Hospital, raised concerns about safety.
The emails were leaked after this newspaper reported 200 patients had been locked in seclusion rooms in the psychiatric unit at Tauranga Hospital in the past three years - one patient spent 173 hours and 53 minutes in a room.
The documents show incidences including staff being punched by patients and one being seriously injured ''resulting in him only been able to work light duties for the past several months''.
''It's distressing witnessing our valued staff members being attacked.''
An e-mail sent on March 5 to colleagues said ''over the past week in the mental health inpatient unit there has been further incidences of violence and aggression''.
Some of the incidents reported included a patient smashing a reinforced glass window, ''causing fear and distress to patients, staff and students alike''.
''The patient was locked in the admission suite and repeatedly banged on the duty room window until it smashed.''
There was no discussion following the event, the email said and patients hid in their rooms.
''My colleagues and I went around that whole night in a state of shock."'
Another involved an aggressive, violent patient in a seclusion room where staff had to call security for assistance and support.
''We were advised security were unable to attend as there was only one security person on for the whole hospital and they were not allowed to leave the Emergency Department.''
An incident form was lodged and the writer said ''I find this situation highly unacceptable ... this is the second time I have emailed management in regards to the health and safety of the staff in this unit.''
''The first time I emailed my concerns I received no reply.''
In a statement, Mental Health and Addictions service business leader Eileen Hughes said the safety of staff was paramount and the DHB had a zero tolerance policy for physical or verbal violent conduct,
Staff were trained for such situations and wore duress alarms.
''If a duress alarm is activated there is an immediate response with appropriately trained staff. Security staff are not routinely used for interventions in Mental Health.''
It was important to remember the majority of people who access inpatient mental health services were not violent and are more likely to have been victims of abuse, stigma and discrimination, she said.
''People under the influence of methamphetamine or other illicit substances can present with unpredictable behaviours and have an increased risk of aggressive tendencies. As with other areas of health, there is a need to ensure appropriate treatment is provided whilst maintaining staff safety.''
Ms Hughes said if an incident of aggression did occur, a debriefing was undertaken with staff and patients following the incident to address issues and offer support.
"If an assault has occurred our staff were supported to lay a complaint with the police and there was additional support available through the DHB and a national training programme for 'Safe Practice Effective Communication' currently being rolled out across New Zealand," she said.
New Zealand Nurses Organisation Bay of Plenty organiser Angela Neil said there were issues around methamphetamine addicts being in the mental health unit.
''Tauranga is not alone and what I would say; is the mental health unit the right place for people on meth? ... it's a national problem. These units were developed for therapeutic intervention ... they can't do therapeutic intervention with someone high on meth.''
Nationally police attended on average 90 mental health related events every 24 hours.
Labour Party Health spokesman Dr David Clark said there was an alarming rise in the number of people committing assaults in mental health facilities and the number of times police were called to the wards had also increased around the country.
Dr Clark said he believed there was pressure put on staff not to report minor incidents because it could reflect poorly on management and ''that should be a concern for all of us''.
Minister of Health Dr Jonathan Coleman said the causes of mental health and addiction were complex.
"There is no simple answer as to why across the world we are seeing increased demand.''
Budget 2017 invested $224 million into mental health services Dr Coleman said and he expected ''to have more to say on the details of the new initiatives being funded in the coming weeks''.
