To stem losses the hospital rolled out an inventory tracking system that holds pictures of the hospital's 28,000 surgical instruments on a database.

The hospital is now able to use images to prove exactly what surgical instrument trays should contain before an operation begins.

This complements the use of digitally etched barcodes on instruments the teaching hospital uses to ensure staff can confirm whether instruments have been used and sterilized, and where they are in the hospital's "supply chain".

Graham King, nursing unit manager of sterilizing services at Westmead, said once the system went live at the end of last year, errors on surgical instrument trays diminished completely.

King said the hospital went searching for the tracking system when the owner of the previously used tracking system refused to commercially release its IP.