Coles is taking extreme measures to combat self-service checkout theft by installing tablet-sized cameras on top of its self-service checkouts in up to a dozen supermarkets across Victoria.

The cameras are installed directly above the self-service monitor, with every move made at the checkout broadcast back to the shopper and recorded on file.

“The trial is still underway in a small number of Victorian Coles supermarkets,” a Coles spokeswoman said.

Eight million self-service transactions are made each week at Coles, with the new security measure to be coupled with undercover security officers already deployed in stores across the nation.

The trial comes after a Coles in northern Sydney installed similar security cameras and screens on top of baby formula shelves to combat bulk buyers re-selling it overseas to Chinese customers.

Overall, theft costs Australian retailers $9.3 billion per year – or 3 percent of their total annual turnover.