A nurse at a Christchurch mental health unit was left with second-degree burns when a patient threw a cup of boiling water over her.
A Canterbury District Health Board spokesperson confirmed the attack took place in the acute inpatient unit at Hillmorton Hospital, a mental health facility, over the weekend.
The Florence Smith nursing Facebook page posted graphic photos of the burns and said the nurse was writing notes in the nurses station when the boiling water was thrown at her, causing second-degree burns and "future scarring, not to mention emotional trauma".
"When questioned why, the patient shrugged their shoulders," the post said.
"She could be your daughter, your wife, your sister, your friend. She is a nurse and there is no excuse. Ever!"
The DHB spokesperson said the nurse was doing well and was in a comfortable condition.
"We are carrying out a thorough investigation into what happened and the circumstances in the unit at that time and will continue to support the staff member with their recovery," they said.
"Specialist Mental Health Services takes all incidents of violence seriously. No level of violence towards staff, patients, or anyone else is acceptable.
"We are taking action to reduce the risk of violence within our service. For example, the Specialist Mental Health Service is working on a project with the New Zealand Nurses Organisation to support a safe and sustainable acute inpatient service.
"The project aims to address assaults and threats, and is looking at ways to proactively and systematically prevent, de-escalate and manage aggressive behaviour.
"The project is also reviewing leadership roles and crisis admission procedures, and taking steps to create a more calming and therapeutic environment."
The weekend's incident was not the first serious assault at the hospital this year.
In March, a nurse was "beaten senseless", another's finger was bitten "to the bone" and a third nurse was hit on the jaw during an assault at Hillmorton Hospital.
The three nurses, from the mental health clinic in Christchurch, ended up in the emergency department after the assault by a patient in a drug-induced psychosis.
A health and safety review was put in place at Hillmorton Hospital in October 2017 after earlier reports of staff being bitten, hit, and injured.
Between January and October last year there were 11 ACC workplace injury claims for staff working in the assessment, treatment and rehabilitation unit.
Four people were also injured after a patient lit a fire at the hospital in December.
Ministry of Health acting chief nursing officer Jane Bodkin said the safety and wellbeing of nurses and other health workers was extremely important and was the joint responsibility of individuals and the organisations they were employed by.
"We are very concerned about the rise internationally, and in New Zealand, of violence against health sector workers and welcome moves to work together to improve safe staffing and healthy workplaces."