Belfast City Council paid more than £292,000 to a fraudulent bank account.
It is one of a number of incidents of fraud and theft involving local councils and detailed in today's report.
In another case, an employee of Fermanagh District Council was sacked after allegedly stealing £20,000.
The report warns the upheaval linked to the move to 11 new supercouncils next year could leave councils more vulnerable.
The biggest incident of fraud relates to Belfast City Council.
In July 2013 it was discovered changes had been made to bank account details held by the council for one of its main contractors.
This resulted in two payments totalling over £292,000 being made to a fraudulent account.
Once the fraud was discovered, payments to the bank account were frozen, the PSNI was notified and an investigation launched.
A police probe found no evidence that either employees of the contractor or council staff were involved.
The council recovered much of the loss from its insurers.
Meanwhile, a second incident involved Fermanagh District Council. An alleged theft by an employee was reported to the council and, after an investigation, the employee was sacked.
The overall loss was around £20,000, although £19,000 of this was recovered from insurers and the loss was reduced to £1,000, the excess on the insurance policy.
The matter has been referred to the PSNI.
A third incident involved Craigavon Borough Council.
It followed complaints from the public regarding alleged requests for money made by staff who worked at Craigavon Council's Fairgreen Recycling Centre.
A Fraud Investigation Team report was completed in September 2010 and the PSNI was informed.
The report concluded fraud had taken place and a disciplinary investigation began resulting in three employees being dismissed.