Australians who recover from a bout of COVID-19 will only need to wait seven days to give blood under a new policy change amid the Omicron wave.

With more than 700,000 active cases isolating around the country - and many more close contacts and people awaiting PCR test results - Red Cross Lifeblood is slashing the recovery wait time to donate blood from 28 days.

The change will be implemented from Friday, while donors started being tipped off on Monday afternoon.

Lifeblood said the 28-day postponement was an important protective measure in the early phase of the pandemic when there was limited knowledge about COVID-19.

But with high appointment cancellation rates and no reports of COVID-19 transmission from blood transfusions after 300 million confirmed cases globally, it has swung into action.

"Following advice from our expert medical teams and with the approval of the Australian regulator, we will be reducing the 28-day postponement for donors who have fully recovered from COVID to seven days," a Lifeblood spokesperson told AAP in a statement.

"The seven-day postponement aligns with public health guidelines. A one-week recovery after mild respiratory illnesses such as a cold and runny nose is already our standard postponement."

There are 4500 appointments going unattended each day at present and the Red Cross is urging more donors to come forward, with an additional 5500 needed every week between now and Australia Day.

"COVID does not stop the need for blood," the spokesperson said.

"There are currently, and will continue to be over the coming weeks, patients involved in road accidents who need large volumes of blood for transfusions, cancer patients who will still need support to survive their treatment, and women who experience complications while giving birth, as well as many others who rely on this precious resource."

Blood donation centres are open every day around the country and anyone willing to roll up their sleeve can contact Lifeblood on 13 14 95.