Red Cross Lifeblood is appealing for 16,000 additional people to give blood or plasma during the next two weeks.

All blood and plasma types are needed, but in particular, supplies of O positive and A positive blood have now dropped to two days' supply.

Lifeblood Executive Director Cath Stone said fewer donors had been making appointments recently and around the nation, 1200 donors each day were cancelling or not turning up for their donations.

Ms Stone said 31,000 donations were needed every week across Australia.

"This recent trend of decreasing appointments and increasing cancellations is concerning."

Around 71 per cent of the Australian population has an O+ or A+ blood type.

Federal Health Minister Greg Hunt on Tuesday donated blood and urged Australians to follow his lead.

"If you can give blood in the next two weeks, that would be great, particularly A positive and O positive but all types are welcome," he said.

"Turns out that mine is A positive, so it is nice to be able to contribute in some small way."

Deputy Chief Medical Officer for Primary Care Michael Kidd said a single donation could save three lives.

"Blood is used to support many people, people who are having major surgery, people who've had accidents, women who have lost blood during childbirth, people with blood diseases, people with anaemia. The list goes on and on," he said.

Australian Associated Press