Supplies of vital blood groups have dropped to "dangerously low" levels, according to the Irish Blood Transfusion Service (IBTS).
Mr Martin Hynes, IBTS chief executive, said he could not guarantee supplies of O and A negative blood over the coming days unless donors with these blood types came forward immediately.
He said cutbacks in the use of blood from people who had spent time in Britain following the BSE crisis, combined with a traditional summer drop in donors, brought about the shortage.
"Deferral of UK donors, introduced because of the increased risk of contracting variantCJD due to the high incidence of BSE in the UK cattle herd at that time, is now taking effect," he said.
Since April 1st, the organisation has refused to take blood from people who have spent five years or more in the UK, but has urged people who have spent less time there to come forward.
The IBTS is also concerned that media coverage of the Lindsay tribunal might be a factor in preventing people from giving blood. "These events happened in the early 1980s. Blood today is as safe as it can be. There's no risk in giving blood."
Mr Hynes appealed to the 8 per cent of the Irish population with O negative blood to help maintain supplies to hospitals nationwide by coming forward.
"Because O negative is the universal donor, their blood can be given to any patient."
Mr Hynes said O negative blood was particularly useful in emergencies, when there might not be time to group a patient's blood. It is also used to treat new-born babies who need transfusions.
"That's why it's very important to have a ready supply of O negative blood in the bank at all times," he said. He also called on the 5 per cent of Irish people with A negative blood to donate.
Donated blood lasts for only 35 days and people who give blood can only donate every three months.
"Seasonal slowdown in people donating blood at holiday periods is a feature of all blood donation services, including the Irish service," Mr Hynes said.
Details of donation clinics and additional information are available on Aertel: page 691; the IBTS infoline 1850-731137 and website www.ibts.ie
