Scammers claiming to be from the Cancer Society are cold-calling people, trying to trick them into making donations they can steal.
The Cancer Society said a 92-year-old woman was cold-called today by a scammer, who asked for her credit card details.
The society said it never cold-called for donations, and the scammers were trying to capitalise on the week leading up to the Daffodil Day appeal.
Chief executive Claire Austen said the tactic was fraudulent and exploitative.
"Basically it's stealing from people with cancer. This is the money that goes towards support services for people and their families who are going through cancer. It really, really is terribly disappointing."
Ms Austen said anyone wishing to make a donation to the society should do so through the Daffodil Day website, the ANZ bank, or a street collector.