Lifeblood Executive Director of Donor Services Cath Stone said other blood types also need a boost, but O-negative blood type was particularly important over the Easter period.

"O-negative is the universal blood type and can be given to anyone in an emergency, such as a road trauma, when there simply isn't time to find out someone's blood type," Ms Stone said.

"Only nine percent of Australians have O-negative blood, but it makes up 17 percent of orders from hospitals because it saves lives in emergencies.

"Our stocks of O and A blood types are lower than we'd like, so an extra 8,000 blood donations are needed immediately to boost blood supplies back to normal levels."

One third of Australia's blood supply comes from New South Wales, and last week's flooding means some of the state's donors were unable to keep their appointments.

Added to this is the upcoming Easter long-weekend, traditionally a challenging time for blood supplies, as many donors take a break.

"Our donor centres across the country will be open over the long-weekend, and I urge Australians who can safely make it to their local donor centre to book an appointment in the place of those who can't," said Ms Stone.

"We understand so much has been asked of Australians over the last 12 months, from bushfires, to the pandemic and now floods.

"While we've appealed for donors multiple times already this year, the number of people responding simply isn't meeting patient demand.

"Even in the face of natural disasters or global pandemics, the need for blood remains and that's why this call-out is so important."

Call 13 14 95 to donate blood.