A security guard was reportedly punched at Hillmorton Hospital in Christchurch this morning.
Canterbury DHB Chief Executive David Meates confirmed the incident took place.
"The staff member is currently being assessed in the Emergency Department and we are providing support to him," he said.
"I vehemently condemn all assaults against staff, patients and visitors."
Police confirmed they were called to the incident and said they are speaking with those involved.
The incident is the second alleged attack on staff at the hospital over the past two weeks.