Report finds federal government failings likely contributed to Ruby Princess COVID-19 disaster

Failings by a federal government border agency likely contributed to the deadly Ruby Princess COVID-19 disaster, a major report has found.

The scathing audit has exposed further errors from when the virus-plagued ship returned to Sydney last March and passengers were allowed to disembark.

And the review catalogues years of problems inside the Commonwealth department responsible for stopping diseases at the border.

"Several issues highlighted in this report ... are likely to have contributed to the Ruby Princess incident in March 2020," the report concluded.

The ABC has uncovered the 200-page probe from an independent Commonwealth watchdog that examined the role of the agriculture department.

The Inspector-General of Biosecurity report details how the officer who inspected the Ruby Princess did not follow protocols, including the "crucial error" of not interviewing sick passengers.

But the report makes clear the disaster followed years of missed opportunities for change, including a 2018 internal audit of biosecurity for arriving ships that was largely not acted upon.

"Frankly, if the department had done what it agreed to do, then the chances of a Ruby Princess incident happening were significantly reduced," Inspector-General Rob Delane told 7.30.