Marie Staunton of Plan UK wants the Charity Commission to produce a how-to guide for charities to help them deal with the scams, which attempt to persuade people to give their bank account or credit card details so their money can be stolen.
"I would like to see the commission pull together best practice advice to help us deal with this," she said. "We need guidance to protect our supporters, our good names and our beneficiaries."
Staunton contacted both the commission and the police last week after at least 17 Plan donors received emails from a bogus programme director claiming to be working on behalf of the charity in South Africa. A scamster calling himself Dr Gary Smith offered donors up to $5,000 (£2,700) a month in commission for processing money as an 'account rep' for the charity.
Although no one fell for the scam, Staunton believes it's only a matter of time before fraudsters convince donors to hand over financial details.
"There is not much the police can do," she added. "We had to go through our local police force, but obviously these people can just disappear."
A spokeswoman for the Charity Commission confirmed that its Charity Services Division was dealing with Plan's request for help. She said the commission was working on new guidance for fundraisers that would take new technology into account, although she was unable to say whether the guide would offer specific advice on phishing. The guidance, she said, was expected "in the coming year".
Since the scam, Plan has issued a warning to donors on its website not to respond to email requests for bank account or credit card details.
The message reminds donors that such requests can look reputable, and offers them a contact name, number and email address for reporting suspicious emails.
The charity also contacted Yahoo and Google, the companies that issued the email accounts to 'Dr Smith'. Both firms closed the accounts.
Plan said it took its cue from the British Red Cross, whose website gives a similar warning. A spokeswoman for the Red Cross said that its donors had not been targeted, but the warnings had been published as a preventive measure.