The Health Service Executive has begun an investigation after it emerged that an agency staff member who worked in several Irish hospitals was infected with the hepatitis C virus.
An expert group has been set up to establish what hospitals the person worked in, what procedures they carried out and whether there is a chance patients could have been at risk.
The HSE confirmed that the person is not currently working in an Irish hospital.
The Health Protection Surveillance Centre is working with hospital management and the expert group to determine what action, if any, may need to be taken.
A HSE spokesman said yesterday that patients will be notified if the expert group concludes they could have been exposed to the virus, which can cause cirrhosis and cancer of the liver.
In 2010, 457 patients were called in for hepatitis tests after it emerged that a doctor had contracted the virus.
Healthcare workers are routinely tested for hepatitis under national guidelines aimed at preventing the transmission of bloodborne diseases.
Those with the virus are not permitted to carry out certain procedures which could expose patients to infection.
The HSE said the risk of patients contracting hepatitis C from a healthcare worker is very low. A recent review of bloodborne virus transmission in Irish healthcare settings found no patients had been infected by a healthcare worker between 1997 and 2008.