The Irish Blood Transfusion Service (IBTS) is to contact approximately 90,000 regular donors over the next two weeks, advising them to visit their doctor if they are experiencing symptoms of anaemia.
Last November it was announced that equipment being used by the service over an 18-month period, from July 2014 to November 2015, was faulty.
The fault in the equipment meant that low haemoglobin levels in donors was not detected, and so donors could have developed anaemia as a result of donating blood.
The IBTS then stopped taking donations from women until the equipment was replaced with functioning devices, and urged concerned donors to contact their GPs if they felt unwell.
They are now contacting all regular blood donors, those who donated a number of times during that 18-month period, telling them that the service will cover the cost of the GP visit.
Letters were sent to donors earlier this week and began to arrive last night.
While the cost of the visits is not known, with no clear number of potential visits estimated at this point, the IBTS says it plans to recoup some costs from the manufacturer of the faulty device - the Haemospect.
The IBTS has assigned extra staff to a helpline set up to field calls from donors. and expects Monday and Tuesday to be days that first batch get in contact with any queries.