"O" positive blood is urgently needed at the National Blood Transfusion Service since only 33 bags that have not been allocated to patients remain.
The NBTS said in an appeal it had 66 "O" positive blood bags, 33 of which were allocated to patients.
"O" positive patients could only recieve "O" positive or negative blood so unless there were donations, some people might not be receiving blood at soon as they needed, it said.