The Irish Blood Transfusion Service is appealing to people to give blood as the current warm weather has seen stocks fall sharply.
According to IBTS Chief Executive Andrew Kelly, donations fell by 26% at some clinics across the country last week.
Mr Kelly said while there is currently a four-day supply of blood, they would like to have a seven-day supply in the bank.
Summertime always presents challenges for the IBTS and it is expecting a further fall in donations with exams and the Euro 2012 championships coming up.
Mr Kelly is urging donors to make a special effort to give blood over the coming weeks.