Whilst it is a mandatory requirement to supply a GTIN (product identifier) for all Amazon listings, you may apply for a GTIN exemption from Amazon for any of your own private label goods that do not have a GTIN.

You can check your eligibility for an Amazon GTIN Exemption here.  If you have your own brand products and your brand name is trademarked you may also be able to apply for Brand Registry with Amazon here

If you receive a GTIN Exemption or register your brand with Amazon you will then be able to list those products on Amazon without needing a GTIN.

If you do receive a GTIN Exemption from Amazon you must provide a copy of the approval details to Omnivore.   After the exemption has been granted we advise waiting for a minimum of 48 hours before trying to list your products on Amazon Australia.

Omnivore communicates with Amazon via the API.  We do not have a way via the API to know that a Brand Registry or GTIN Exemption has been granted for specific categories or brands on your account.   Therefore we are not able to automatically detect which brand or category will allow a merchant's product listing without a GTIN.

More Reading

Amazon and ASIN creation.