The IBTS is calling on people to make a special effort to give blood, after clinics nationwide were cancelled due to the impact of Storm Emma.
Operations Manager Paul McKinney is calling on people to attend the clinics.
"We have three days supply across all blood groups," he says, "so we are asking people to make a big effort to attend."
"We have put on an extra day this Sunday, but we are in Waterford (Woodlands Hotel) until Thursday, so it is a really important clinic for us."