The Irish Blood Transfusion Service has issued an urgent appeal for people to donate blood.
It says supplies have fallen to a level that is only sufficient for three days.
That is just under half the required level for an average week.
Dr. Paul McKinney of the IBTS says current blood stocks are at a crucially low level.
"We are well short of where we need to be to ensure we continue to supply hospitals, where blood demand has been very high for a sustained period.
"It's quite critical that we get our stocks back up."
