Paying the correct postage
When sending parcels or letters through our network, it’s important you apply the correct postage before posting them.
Read our size and weight guidelines to check how length, width, thickness and weight affect the total postage cost.
If your letter exceeds our maximum size and weight limits, it will be considered a parcel. If you need help weighing your letter, visit your nearest Post Office.
Delivering mail with incorrect postage
We may still deliver an item even if it doesn’t have enough postage. However, we may issue an Underpaid Mail invoice to the sender to cover the balance of the postage, as well as an administration fee.
In some cases, we may:
- hold the item until the correct postage is paid, or
- seek payment from the receiver if we can’t identify the sender.
For more details:
- Read section 4.7 of the Australia Post General Terms and Conditions (PDF 1.64MB) for details on how we recover underpaid postage.
- Read our Post charges guide (PDF 813kB) for information on the Underpaid Item administration fee.
Sending with counterfeit products
When a parcel or letter is sent with counterfeit stamps or prepaid satchels, we classify it as Underpaid Mail.
When detected, or if we determine that a sender consistently posts items with underpaid postage, we may:
(a) refuse to carry the item; or
(b) hold the item and notify either the sender or the receiver that proper postage plus an administrative fee (as set out in the Post Charges Guide (PDF 813kB) is payable before we deliver the item. If these costs are not paid within seven days, we may deal with the item under clause 4.6(d) as outlined in the Australia Post General Terms and Conditions (PDF 1.64MB).
Using stamps or prepaid satchels not issued or authorised by Australia Post, even unintentionally, is a breach of our terms and conditions. It may also be an offence under the Crimes Act 1914.
We recommend purchasing Australia Post stamps and prepaid satchels only from Australia Post outlets or our Online Shop.
Frequently asked questions
You received an Underpaid Mail invoice because your mail item/s had insufficient postage.
In general, your invoice will tell you the number of underpaid items that were detected (“Qty”), how much postage was paid (“Postage Paid”), how much postage should have been paid (“Correct Postage”), the amount owing per item (“Deficiency”), the administrative fee payable (“ Admin Fee”), and a total (“Total Amount due inc. GST”).
For customers with a business credit account, postage meter underpayments will be included in your tax invoice. The invoice will detail the deficient postage charges grouped by the Letters product category, while the administrative fee payable will be listed under "Metered Mail: Underpaid Items."
The invoice will include details of the postage meter underpayment charges. The Statement Summary will label deficient postage charges as “Deficit Postage xx,” where “xx” represents the number of items with underpaid postage. The underpaid item administration fee is labelled as “Underpaid AdminFee.” Additionally, “No Postage Paid xx” indicates items lodged with no postage paid, with “xx” referencing the number of items with no postage.
This information should help you identify any postage calculation errors so you can apply correct postage in the future.
For more help assessing the correct postage to pay, please see our handy guide.
As part of our compliance checking, your mail was detected as being underpaid. Our classification of mail has not changed, and it is likely that your previous incorrect mailings were not detected.
Please ensure you review the correct postage for any future items you are sending to avoid receiving future invoices for underpaid mail.
Please read our postage guide to learn how your item’s length, width, thickness, and weight affect the total postage cost. Where an item’s dimensions, weight or thickness are outside what is allowable for a letter, it must be charged as a parcel.
If you require additional assistance or advice, our friendly team at your local Post Office can help you understand measurements and sizing for correct postage calculation.
Under Section 4.7 of the General Terms and Conditions (PDF 1.64MB), an administrative fee is payable in addition to the underpaid amount where actions to manage underpaid mail have been required.
Australia Post sets and publishes the Underpaid item administration fee in its Post charges guide, and provides a summary total of these charges on your invoice as “Underpaid Admin Fee”. We apply a cap of the fee to 40 items per lodgement.
To avoid this charge in future, please ensure correct postage is paid before posting.
The majority of our business bulk mail services, such as Imprint Mail, Pre-sort Mail, Unaddressed Mail (and others) cannot be lodged in a street posting box and must be lodged over the counter. An exception of this is Metered Mail which can be lodged in a street posting box.
Please see your service agreement terms for your individual lodgement obligations or contact our team on the details below if you require further information.
If you have inadvertently lodged such mail, please call our Business Support Team on 13 11 18 Mon-Fri (excluding national public holidays) from 8am-6pm AEST.
If you would like to explore our range of business bulk mail services, please visit our bulk mail services guide.
Before disputing your invoice, please read the postage guide; postage for sending a letter is determined by size, thickness and weight – items that exceed letter maximums must be sent as a parcel.
If you feel you’ve been invoiced incorrectly, please complete an enquiry form on our support page, making sure to describe the details of your invoice, including the Date of Issue and Billing Number, along with the details of your query. One of our helpful team members will investigate and assist you.
Information on how to pay is provided on your invoice, including by Post BillPay (online or in store), or at any Australia Post Office.
If you are a business customer, you may add the invoice to your Australia Post Business Credit Account if you have one, by completing the Business Credit Account portion of the invoice and returning it to Australia Post.
If you would like more information about establishing an Australia Post Business Credit Account, please see our information page here.
If you need any further help regarding your underpaid mail, please complete an enquiry form on our support page, detailing your query.
One of our friendly team members will assist you.