Safeguarding Ireland is encouraging people who are experiencing alleged abuse to report it to HSE Safeguarding Teams.
New figures show only 2% of them are coming forward and almost all cases reported to the health authority are through staff and families.
Vulnerable adults including frail older people, those living with dementia, a brain injury or a mental illness are most at risk of abuse.
HSE National Safeguarding Office General Manager Tim Hanly says it can be hard to report it when they are living with or relying on the person.
"If it's a family member of someone who is very close to them as a carer then it may be difficult for them to come directly to us in the health service.
"That's why often they go through another family member or a healthcare professional."