Many nurses and midwives do not report the incidents that take place in hospitals, it said.
The Irish Nurses and Midwives Organisation has called for increased security across all areas of hospital campuses.
Soothing words from employers and an acknowledgment of the scale of the problem is not enough for members at this stage, the INMO has said
This comes as figures reveal that over 5 nurses were physically, verbally or sexually assaulted a day in the month of June.
In 2021 the Health and Safety Authority recorded 7477 inspections but only 446 inspections in health and social care settings, compared to 2865 in construction
Naas resident and INMO General Secretary Phil Ní Sheaghdha said: “These assault figures are unacceptable and unfortunately not news to our union. As we continually highlight overcrowding, Covid care and its restrictions and poor staffing levels all add to this increasing problem.
"Nurses are facing the brunt of physical and verbal aggression in hospital. In some cases, our members are victims of career ending assaults.
"Anecdotally we know that many nurses and midwives do not report many of the incidents that take place in our hospitals because they do not have support to do so.
“The pressure cooker type environment that our members work in is leading to more assaults. This means that frontline staff are being put at risk for conditions they are not responsible for.
“Ensuring security is available across all areas of any hospital campus is a basic need that is not fulfilled in every hospital.
"While we see high levels of assaults in our Emergency Departments, we need to have 24-hour security in all areas of hospitals not just Emergency Departments. Many assaults are occurring in parts of hospitals where security staff are not available.
“Soothing words from their employer and an acknowledgment of the scale of the problem is not enough for our members at this stage.
"In the last year, 90% of our members reported being mentally exhausted during or after work. Inadequate safety protections only add to the burnout.
“Nurses and midwives need hospital management to use the powers they have and support staff and make complaints to Gardai - zero tolerance is required and that is not the case at present.
"The Health and safety Authority need to play an enhanced role in tackling assaults of nurses. There must be more inspections, prosecutions of employers who fail to keep staff safe.
"There must be a dedicated division established within the HSA to deal directly with the health service. This is an ask the INMO has put directly to Government and the Authority itself.
“Hospitals are not just places of care, they are workplaces. We need to know what measures are being put in place to protect a largely female work force. The employer’s remit is to provide a safe workplace.
"This level of reported incidence is completely unacceptable," she added.