An independent confidential helpline should be established to encourage health service staff to raise concerns, a regulator said.
A significant minority did not flag up issues because some felt nothing would be done and feared reprisals, the Regulation and Quality Improvement Authority (RQIA) said.
Its review warned staff must have the confidence to bring forward any concerns without fear, knowing that any genuine matter will be treated seriously and investigated appropriately.
RQIA chief executive Olive Macleod said: "It is not acceptable for organisations to assume a low level of raising concerns is positive; they must each test the silence to gain assurance that the process of raising concerns is working well in their organisation."
It said whistleblowing was mostly seen as a negative term, fuelled by media focus on the personal ordeal of whistleblowers.
The review said a positive step in encouraging the raising of concerns would be the development of an independent helpline to provide advice and support for health and social care staff in Northern Ireland.
It is recommended that this should be run as a pilot, with a subsequent evaluation to decide on whether or not to continue it.
Ms Macleod said: "While many staff raise concerns, a significant minority do not, with some feeling that nothing will be done, and fear reprisal.
"An open and honest reporting culture gives staff the confidence to bring forward any concerns, without fear, in the knowledge that genuine concerns will be treated seriously and investigated appropriately."
She said responding to whistleblowing in a timely manner was key to supporting improvement in the quality of health and social care services and assuring patient safety.
The review team made 11 recommendations to improve whistleblowing arrangements within health and social care organisations, including the development of a model policy for raising concerns.