Charities lost almost £8.6m to fraud during the last financial year, according to new figures published by the regulator.
The Charity Commission has marked the start of Charity Fraud Awareness Week by warning charity leaders to “take action on fraud” to protect their organisations against cybercrime.
The annual campaign aims to highlight ways charities can protect themselves from this crime.
The new figures, from Action Fraud, show 1,059 separate incidents of fraud were reported by charities between April 2020 and March 2021.
The new figures are more than double those reported in October last year, which revealed £3.6m in total losses to charities since the start of the pandemic in March 2020.
The commission said the true scale of fraud against charities was believed to be much higher because fraud was known to be underreported.
Additional figures released today show that about two-thirds of charities feel the pandemic has increased their risk of fraud.
Charities also expressed concerns that risk may have been increased as a result of more remote working and virtual sign-off processes.
Last month, HM Revenue and Customs warned charities to watch out for bogus tax rebate or refund requests after officials said they had identified about 1.5 million scams across the UK during the pandemic.
Together with the Fraud Advisory Panel, the commission is urging all trustees to sign up to a new Stop Fraud Pledge, which commits charities to taking six practical actions to reduce the chances of falling victim to fraud.
The pledge includes measures such as appointing a suitable person to champion counter-fraud work throughout the organisation, performing stringent checks and due diligence, assessing each year how well fraud controls are working, what new risks there may be and what improvements are needed.
Helen Stephenson, chief executive of the Charity Commission, said: “Sadly, as these figures we have released today show, there remain criminal individuals who would take advantage of organisations that seek to do good and of those that generously donate.
“Combatting fraud gives the public confidence that their money is safe, protects vital funds for charities and more widely helps maintain trust in the charities we all care so passionately about.”
David Clarke, chair of the Fraud Advisory Panel, said: "It is concerning that a small minority of charities still do not financially invest in fraud prevention activities.
“This shows that there is still more to be done.”
Charities that are concerned they have been the victim of fraud or cybercrime should report it to Action Fraud and as a serious incident to the Charity Commission.
Individuals can also report phishing messages to the National Cyber Security Centre through the Suspicious Email Reporting Service.
Last year, more than 100 charities were caught up in a ransomeware attack on the software company Blackbaud.