The Irish Blood Transfusion Service (IBTS) is urgently seeking an additional 12,000 blood donations over the next four weeks as most blood groups have fallen to under three days of stock.
IBTS Service Director of Donor Services and Logistics Paul McKinney has warned that hospitals may be asked to cancel some elective surgeries if blood supplies are not significantly boosted.
Mr McKinney said current supplies are under three days for most blood groups, when seven days' supply is generally needed.
"Despite strong collections over the last two months, high hospital demand and increasing levels of respiratory illness within the community has impacted our collections and we need the public's help," he said.
Speaking on RTÉ’s Morning Ireland, Mr McKinney said the demand for blood donations is increasing because hospitals are getting busier.
He also warned that the IBTS could be required to issue an amber alert, which the service has never had to do before and would impact on elective surgical procedures that require blood support.
"They are doing more surgeries. And last year, we issued just under 129,000 units, which was the busiest year in ten years, and we are tracking to beat that by a considerable amount this year, which is putting us under pressure."
The appeal for more donations is being made ahead of the bank holiday on 27 October.
The service is asking regular donors who are texted for upcoming clinics over the coming weeks to make an extra effort to attend which it said is vital to address the increased demand from hospitals.
The IBTS is particularly encouraging new donors of African heritage to join the national blood donor panel to help diversify the donor base and improve blood type matches for patients.
Potential new donors can visit giveblood.ie and take an eligibility test or call the service directly at 1800 731137 to make an appointment.
