The abolition of cheques could leave small charities especially vulnerable to fraud, according to a specialist in small charity accounting.
At the end of last year, the Payments Council decided that cheques would be withdrawn by 2018, forcing charities to rely increasingly on electronic payment methods.
John O'Brien, chief executive of financial advice charity CA Plus and chair of the Community Accounting Network, said small charities were obvious targets for fraudsters because a lot of information about them was in the public domain.
"It would be easy to set up fake payments," he said. "It doesn't take a genius to work out that any charity's signatories will probably be the chair and the treasurer."
Frances Moore, chief executive of small grant-making charity the RL Glasspool Charity Trust, said she was worried that a move towards online banking would make it more difficult for charities to claim their money back if they were defrauded.
"Trustees are normally required to sign an indemnity saying they will cover the bank for all losses apart from those due to bank error or negligence," she said.
"With forged cheques, the bank will reimburse funds unless it can show that trustees have been negligent. With electronic banking, the onus is on trustees to show that the bank has been negligent."