Blood service swamped after donation plea

Almost 8000 Australians have answered the blood bank's call for O-negative blood donations after supplies fell critically low.

The Australian Red Cross Blood Service on Tuesday said it had just two days' worth of O-negative blood left - the universal type given to patients when their blood type is unknown.

Donors flooded blood service hotlines and the website, the service said in a statement on Wednesday.

Australians are being urged to continue rolling up their sleeves though with concern now turning to July as cold and flu symptoms continue to hamper donations.

The Red Cross blood donor hotline is 13 14 95 or visit donateblood.com.au.