Patient medical records can be disclosed without consent when it is necessary to protect others from serious risk of death or harm.
Guidelines set by the Medical Council state that the sharing of information may be justifiable in exceptional circumstances in the public interest.
They also say that in certain limited circumstances, disclosure may be required by law.
These include when ordered by a judge in court, by a tribunal or a body established by an Act of the Oireachtas or where mandated by infectious disease regulations.
Section C of the Medical Council's Guide To Professional Conduct And Ethics For Registered Medical Practitioners said all doctors and consultants have a duty to maintain accurate and up-to-date patient records.
Patients are entitled to expect that information about them will be held in confidence, even after death, but data protection legislation only applies to an individual's personal records while they are alive.
The council's guidelines also warn medics to report any serious adverse event that harmed a patient, or a near miss, to the appropriate health authority and relevant statutory agency to improve practices and learn from errors.
The Medical Council said most people understand and accept that information must be shared with other healthcare professionals to provide safe and effective care.
"When patient information is to be used as part of clinical audit and quality assurance systems, you should anonymise the information as far as possible," it stated.
"Where anonymisation is not possible or appropriate, you should make patients aware that their identifiable information may be disclosed for such purposes. They should have the opportunity to object to disclosure of their information and any such objection must be respected."