Checking an ABN means confirming the number on an invoice is valid, active and, if GST is charged, registered for GST.
Before you start
- Sage 300 Accounts Payable
- A/P security authorisation for the screen
The Sage 300 way
Where to find it: Accounts Payable > A/P Vendors > Vendors > Business Reg. No. (or an optional field)
- Open A/P Vendors and select the vendor.
- Enter the ABN in Business Reg. No. (the guide says this is the vendor's business registration number, used for tax in some places). The tax group area also takes a tax registration number.
- Check the ABN yourself on ABN Lookup. Sage 300 does not check it.
Limits in Sage 300
- No ABN Lookup check or ABN format check was found in Sage 300.
- Optional fields can hold extra data, but they need Transaction Analysis and Optional Field Creator.
The Pulsify way
- Forward the supplier's invoice to Pulsify.
- Pulsify checks the ABN against the ABR. It flags an invalid ABN, a missing ABN and an ABN not registered for GST when the invoice charges GST.
- It also flags an ABN that differs from the one on the vendor record in Sage 300.
- Fix the vendor record or query the vendor, then approve.
Pulsify connects to Sage 300. We set up the connection for you.
What Pulsify does not do here
- If the ABN lookup is not available, Pulsify flags that it could not validate.
Common mistakes
- Assuming Sage 300 validates the number typed into Business Reg. No.
- Planning an ABN optional field without Transaction Analysis and Optional Field Creator.
More help
- How to check a vendor's ABN in Business Central
- How to check a vendor's ABN in MYOB Acumatica
- How to check a supplier's VAT number in Sage 200
- How to control vendor bank detail changes in Sage 300
- How to report contractor payments for TPAR from Sage 300
- How to check GST coding on vendor invoice records in Sage 300 before you lodge your BAS
- All Sage 300 how-to guides
- Pulsify setup guides
Sources
Last checked 2026-10-19. Confidence: partial.
Common questions
Where does the ABN go in Sage 300?
In A/P Vendors, enter it in Business Reg. No. The guide calls this the vendor's business registration number. It does not name the ABN, so using it for the ABN is a practical choice.
Does Sage 300 check the ABN?
No ABN Lookup check or ABN format check was found. Check the ABN on ABN Lookup yourself.
Can I add a separate ABN field?
Optional fields can hold extra data, but they need Transaction Analysis and Optional Field Creator.
What does Pulsify check?
Format, ABR status, GST registration and a match with the supplier record.
Pulsify setup guides
Want this done for you?
Book a call to see how Pulsify handles supplier bills in Sage 300.