At least two shipments of firearms and gun-parts have slipped through Australian ports in the past month without being detected and stopped by authorities in a breach of import regulations and procedures that has sparked an official investigation.

The legally ordered, clearly marked, consignments, which included a shipment of 12 gauge shotguns and a second large parcel of dozens of rifle magazines, ended up being handed straight over to couriers instead of being halted at the port and impounded by the Australian Border Force (ABF) for supervised official release to the dealer.

At least two shipments of firearms and gun-parts have slipped through Australian ports in the past month.

Gun dealers were horrified to then have the weapons in cardboard boxes turn up on their doorstep instead of being stopped and held at a secure ABF-monitored facility where they could be signed for and picked up legitimately.

One of the businesses involved was a suburban firearms dealer in Brisbane.