People with haemophilia who may have received blood products to treat their condition prior to 1992 but who have not yet been tested for HIV or hepatitis C are being urged to come forward now for screening.
All this week special helplines and clinics will be manned so that those who have not been tested can be checked without delay.
The move is an attempt to find anyone who may be living with either condition but not showing symptoms.
Dr Barry White, national haemophilia director, said the likelihood of somebody with haemophilia having received infected blood products in the 1980s and 1990s and of them living with HIV and showing no symptoms before now was just 2 per cent. But they could be infected with hepatitis C and be showing no symptoms, he stressed.
There have been several appeals over the past few years to get those who may have been infected from imported clotting agents or clotting agents made by the Blood Transfusion Service Board to come forward for testing. At this point, Dr White said, if any infected patients were found in this appeal, the number would be in single figures.
"We do not anticipate we will pick up a large number of people from this programme because there were six previous ones, but if we were to identify one single person it would be worthwhile."
Synthetic blood products have been used since 1997 to treat haemophilia and these posed no risk of infection.
Furthermore, Dr White added, if HIV and hepatitis C infections were picked up now, much improved treatment regimes were available.
On average about half of hepatitis C infections could be cured, for example, and people could lead normal lives on the treatments now available for HIV.
There are 1,382 patients with haemophilia and related bleeding disorders registered in the State. Dr White said that in an ideal world he would like to trace each blood product given to haemophiliacs over the years back to the patients who received them but this was not possible because of poor record-keeping in the past. This was referred to at the Lindsay tribunal, which inquired into the infection of haemophiliacs with HIV and hepatitis C.
The helpline numbers are: National Centre for Hereditary Coagulation Disorders 1800 200 849, open daily 10am-4pm; Irish Haemophilia Society at 1850 872 872, open 8am-7pm; and Irish Blood Transfusion Service 1800 222 111, open 10am-6pm. All help lines will close on Friday.