The Health Services Union is demanding action after a spate of attacks on staff at Bulli Hospital in the last month.
According to the union, one health and safety assistant (HASA) was punched in the face and another in the genitals while a nurse was choked and two others required physio after being attacked by patients.
Bulli Hospital provides a combination of inpatient, outpatient and community health services and specialises in multidisciplinary geriatric care.
HSU NSW secretary Gerard Hayes said understaffing at the hospital was putting pressure on all staff.
"Staff at Bulli Hospital should not have to put their own health and safety on the line simply to do their job. This is simply unacceptable," he said. "Budget cuts are again playing havoc with the ability of our members to work safely and securely.
"We are seeking a commitment from management that at least two health and safety assistants are on shift at any one time. Anything less than that puts our members at risk."
NSW Nurses and Midwives Association regional organiser Mark Murphy said hospital staff should be protected at work.
"The association is aware there's been a number of extremely aggressive incidents involving our members," he said.
"Members of the [union] branch at Bulli have met with management and an action plan is being worked through to ensure our members' - and other patients' - safety in the future.
"It is unacceptable in today's society for our members to be injured by patients in the workplace."
Mr Murphy said branch were meeting on Tuesday to discuss the issue further.
A hospital worker, who did not wish to be named, contacted the Mercury about the assaults.
The worker said staff were concerned for their safety and wanted more security backup.
"Speaking from my point of view, I've had to take patients down when there has been no other alternative," the worker said.
"If I hadn't have intervened a staff member would have been seriously assaulted or killed."
A spokesperson for Bulli Hospital said the hospital worked hard to implement strategies to deal with challenging patients.
"Bulli Hospital treats many patients, most of whom are elderly and living with degenerative conditions like dementia, which can result in aggression in some people," the spokesperson said.
"As part of the management plan for aggressive or challenging patients, the hospital has worked extensively, over the past 12 months in particular, to develop a range of strategies, programs and education for staff with organisations including Alzheimer's Australia.
"These are aimed at striking a balance between maintaining the care, dignity and respect of our patients, regardless of their condition, and the safety and well-being of all staff.
"This can be a challenge, but the hospital is working extremely hard to implement strategies to best deal with caring for people with complex requirements; this includes ensuring an appropriate number of staff on both night and day."
The hospital spokesperson said all of the action plans, patient management strategies and hospital processes were constantly reviewed, amid consultation with staff and other experts.
"Staff are always encouraged to provide feedback or discuss any concerns. To date, this [recent] matter has not been raised with hospital management by staff or unions," the spokesperson said.