If your Amazon SKU does not match the Omnivore product SKU then you will need to delete your Amazon products and listings before you Start Selling to Amazon Australia. 

The steps you need to take in your Amazon selling account are:

Retailers with Existing FBA Listings

If you have existing FBA listings, Omnivore will "ignore" them so do not delete or zero them in the Seller Centre.

Please use the Amazon Seller Centre filters to make sure that you are only affecting the listings for your "Merchant" products. This is selected under the Filter for "Fulfilment Type".

Be very careful with the below steps so that your FBA listings remain untouched.

Step One: Update all inventory quantities to Zero in Amazon Seller Centre

If you are migrating from another integration tool it is important that the tool has been disconnected before completing this step.

To remove your offer from the Amazon detail page, update the inventory quantity to zero and then delete the SKU. If the inventory is not updated to zero, the offer will remain live on the offer listing page as SKU deletion and inventory quantity deletion are separate operations. 

To change your inventory quantities to zero go to Inventory->Manage All Inventory

If you want to bulk update the SKUs to 0 inventory please see this article

Step Two: Delete All Products and Listings in Amazon Seller Centre

From the same Manage Inventory page, you can delete multiple listings by ticking the box to the left of each product listing, clicking the Edit drop-down menu on the right and then selecting Delete product and listing from the Action drop-down menu at the top of the page.