The Irish Blood Transfusion Service (IBTS) has begun contacting 28 donors who were not immediately informed of positive test results for hepatitis C in the early 1990s.
A spokesman for the agency said it had sent letters late last week to at least half of the donors, and the rest should be informed within about a week.
The move comes ahead of a fresh investigation into the delay in telling donors of hepatitis C test results, an issue which first came to light during the Finlay tribunal when the IBTS's regional director in Cork revealed that her practice had been to withhold certain preliminary test results from donors as she believed they might cause unnecessary alarm.
Such patients included a man with the pseudonym Donor L, who was not informed of his positive status until November 1993. Screening for hepatitis C anti-bodies had been introduced two years earlier, and Donor L had donated blood six times in the interim.
Donor L has now begun legal proceedings against the IBTS, which was formerly known as the BTSB. His action has been followed by an announcement by the Minister for Health, Mr Martin, to establish a fresh inquiry into the delay.
The IBTS spokesman said all 28 donors were aware of their positive hepatitis C status, and "it's just the delay aspect that they were unaware of".
However, Ms Detta Warnock, an executive member of Positive Action, which represents women infected with hepatitis C through Anti-D, said: "We only have the BTSB's word for that". She said it was one of a number of issues which would be examined by the group once all the donors had been informed.
Ms Maura Long, chairwoman of Transfusion Positive, which represents people infected through blood transfusions, said the delay in telling people about their test results was of concern, first, because it may have contributed to onward infections, and, second, because it deprived people of immediate treatment for hepatitis C.
It is understood a number of individuals are considering suing the IBTS over the matter, like Donor L.
Mr Martin has yet to decide on what type of inquiry should take place into the issue. The IBTS is in favour of a judicial inquiry while support groups want a full statutory inquiry similar to the Finlay and Lindsay tribunals into the blood scandals.
