COVID-19 restrictions, including lockdowns, have hit donor rates, and the Australian Red Cross's Lifeblood division is appealing for people to come forward.

Australia needs nearly 7000 donations in the next fortnight and to double appointments through until Christmas, donor services director Cath Stone said.

"Unfortunately COVID lockdowns, a change in people's movements and lifestyles, and general social anxiety has led to many of our wonderful donors cancelling their regular donations, or simply failing to show up," she said on Tuesday.

"Our message today is 'please come back'."

Australians are still getting the blood supplies they need, but ongoing reluctance to donate could lead to shortages.

"We'd especially love to see people with O-positive and O-negative blood types book their donation soon," Ms Stone said.

Information, including eligibility to donate blood, can be found at www.lifeblood.com.au

Australian Associated Press