Battle organisers have moved to reassure people that they have taken steps to rectify the problem and the matter has been referred to the Office of the Information Commissioner.
They have advised anyone who receives a suspicious email to flag it as junk.
The States police have also been informed, they added.
Event director Jackie Donald said the organisation had been aware of the issue since September and had updated their security, but emails were still being sent.
The email, which includes a US address and phone number, tells the recipient they have an outstanding invoice from the Battle of Flowers that they need to pay. However, it does not provide any further information about how to pay.
Mrs Donald said the Battle does not keep anyone’s personal information and most people had phoned or emailed the organisation first to check the information contained in the email.
She added: ‘We have made every effort we can. These aren’t real. Please put these emails in your spam folder.’
