National reserves of O+ and A+ blood are at critical levels, the Blood Transfusion Centre warned on Wednesday morning.
"The urgency is still in force. The reserve is still critical. Today we need O+ and A+ blood donors.
"Operations will be cancelled if the blood reserves do not improve," the centre said in a statement.
Those interested in donating blood can call the donation centre on 2206 6201, 7930 7307 or 8007 4313 for more information.
The centre is open every day, including Sundays and public Holidays, between 8am and 6pm.
Gozo blood donation sessions are held at Xewkija Berga on alternate Sunday mornings and alternate Tuesday afternoons, with dates available here.
Prospective donors must take with them a valid photo identification such as an ID card.