The IBTS says it cannot run its traditional Sunday clinics
The Irish Blood Transfusion Service (IBTS) is urging donors to make a special effort and give blood this Christmas time.
The IBTS is concerned that blood supplies will be difficult to maintain between now and the end of the Christmas and New Year period.
It expects that 10,000 donations - some 13,000 attendances - will be needed.
The IBTS says: "Traditionally holiday periods and especially the lead into the Christmas/New Year festivities present significant difficulties in sustaining the blood supply.
"In addition, with both Christmas Day and New Year's Day falling on the Sunday, we cannot run our traditional Sunday clinics during that period."
The IBTS says low attendances at clinics in recent weeks have seen supply for some blood groups drop to just four days.
It says while additional clinics will assist with this, it is also important the clinics of Christmas week are well attended to maintain the blood supply.
"There will be additional pressure in supplying maternity and children's hospitals who only use blood for very young children that is no older than five days", it adds.
To boost supplies, the IBTS is running extra additional clinics on Sunday December 18th in Dunshaughlin, Carlow, Perrystown (Dublin), Scariff and Roscommon town.
While its collection teams will all be out the week prior to Christmas, and the week after Christmas Day.