Duplicate Payment Fraud
The same invoice, paid twice. Whether it happens by mistake or by design, duplicate payments drain money from your business. Most are never detected, let alone recovered.
What is duplicate payment fraud?
Duplicate payment fraud occurs when the same invoice is paid more than once. It is one of the most common accounts payable errors and one of the easiest fraud vectors to exploit. The result is the same either way: money leaves your business that should not have.
Accidental duplicates happen more often than most finance teams realise. An invoice is entered into the system twice because it arrived by email and by post, or because a staff member processed it without checking whether it had already been paid. These errors are especially common during high-volume periods like end of month or end of quarter.
Deliberate duplicates are harder to spot. An insider or external actor submits the same invoice with a slightly modified invoice number, routes it through a different approver, or resubmits it months later hoping no one checks. Combined with fake invoice tactics, duplicate payments become a reliable way to extract money without raising alarms.
How duplicate payments happen
Duplicate payments exploit gaps in your accounts payable process. Here are the most common scenarios.
Same invoice, different channel
A supplier sends an invoice by email. A copy arrives by post a few days later. Both are entered into the system by different staff members, and both get paid.
Slightly modified invoice number
The invoice number is changed from INV-2024-0891 to INV-2024-891 or INV2024-0891. The system treats it as a new invoice because the number does not match exactly.
Different approver path
The same invoice is submitted to two different approvers. Each assumes the other has not seen it. Both approve, and the payment runs twice.
Delayed resubmission
A copy of a legitimate invoice is submitted weeks or months later, banking on the fact that no one will remember or check whether it was already paid.
Warning signs of duplicate payments
Duplicate payments leave patterns. These are the signals your finance team should be watching for.
Sequential but slightly different invoice numbers
Invoices from the same vendor with numbers like INV-0891 and INV-891 or INV-0891 and INV-0891a. Small variations that bypass exact-match duplicate checks.
Same amount, same vendor, short timeframe
Two payments of the same amount to the same supplier within days or weeks. Legitimate if it is a recurring charge, but worth investigating if the amounts are irregular.
Invoices without purchase order references
Invoices that arrive without a PO number are harder to match against existing records and more likely to slip through as duplicates.
Round-number invoices
Invoices for exactly $5,000, $10,000, or other round amounts are easier to duplicate because they do not stand out as unusual. Legitimate invoices typically have specific amounts.
Multiple payment methods for one vendor
If a supplier is paid by EFT one week and by cheque the next for the same invoice, the duplicate may not appear in a single payment register.
Invoices processed by different staff
When the same invoice is entered by two different accounts payable staff members, neither may know the other has already processed it.
How ezyshield prevents duplicate payments
ezyshield fingerprints every verified payment detail. Duplicates become visible before money moves, not months after.
Payment fingerprinting
Every verified payment is fingerprinted: payee, bank account, and amount. If the same combination appears again, it is flagged before the payment is processed.
Pre-pay run re-verification
Before every pay run, ezyshield re-checks all payment details. Duplicate payee and amount combinations are surfaced automatically, whether they were submitted days or months apart.
Tamper-proof audit trail
Every payment verification is logged with timestamps and full detail. Duplicates that were missed in real time become visible in the audit trail for review.
Frequently asked questions
What is duplicate payment fraud?
How common are duplicate payments in Australian businesses?
What is the difference between accidental and deliberate duplicate payments?
How does ezyshield help prevent duplicate payments?
Related content
Insider Threats
How employees exploit payment access to redirect funds or create fictitious suppliers.
THREATFake Invoice Scams
Fraudulent invoices that slip through AP during high-volume processing.
LEARNAP Fraud Prevention
A complete guide to protecting your accounts payable process from fraud.
PRODUCTHow ezyshield Works
Payment fingerprinting and re-verification that catches duplicates before you pay.
Stop paying the same invoice twice
ezyshield fingerprints every payment and re-verifies before every pay run. Duplicates get caught, not paid.