What this means
If you see an error like:
“Package weight 10kg exceeds maximum weight 5kg for Flat Rate Packages (FLAT_RATE_BOX_MEDIUM).”
It means the total weight of your order is over 5kg, which is the maximum allowed for Australia Post Flat Rate packaging.
How to fix it
You have two options:
Use your own packaging
Switch the package type from Flat Rate to your own packaging.Weigh the actual parcel, and reduce the order weight
Adjust the order so the total weight is 5kg or less, but ONLY if the parcel weight falls below the maximum.
Important
If you manually lower the weight to 5kg to access Flat Rate pricing, but the parcel actually weighs more:
Australia Post will issue an Underpaid Postage charge
Additional fees may apply
Always ensure the weight you enter matches the actual parcel weight to avoid extra costs.