Authorities made serious errors by failing to test a new classification of suspected COVID-19 passengers on board the ill-fated Ruby Princess cruise ship.
That's one of a raft of findings from a special commission of inquiry into the vessel's arrival in Sydney on March 19, when numerous contagious people disembarked at Circular Quay, and subsequently spread the virus across Australia and overseas.
After hearing weeks of evidence, the Special Commission of Inquiry commissioned by the NSW government on Friday released its findings.
The report noted that on March 10 the Communicable Diseases Network of Australia amended its guidelines such that everyone on board the ship with newly-defined suspect cases should be tested.
But when a risk assessment was conducted on March 18, those making decisions did not have the updated definition of a "suspect case".
"This was a serious and material error," the commission found.
The Ruby Princess has been linked to hundreds of cases and more than 20 coronavirus-related deaths across Australia.
The ship - which was low on medical supplies and swabs for COVID-19 tests due to shortages - left Sydney on March 8 for New Zealand and returned 11 days later.
Despite the respiratory symptoms of numerous of those aboard and uncertainty surrounding test results, 2700 passengers were permitted to disembark as the voyage had been deemed low risk by NSW health authorities.
This is because only 0.94 per cent of passengers presented to the ship's medical centre with flu-like symptoms - not the one per cent required to mandate NSW Health intervention - and none had visited virus-hit countries China, Italy, Iran or South Korea.
Passengers disembarked before the results of 13 expedited tests showing at least three people had the virus.
Bret Walker SC was tasked with examining the ship's departure, arrival and disembarkation and conducted 21 days' of hearings from April to July.
Separate NSW Police and coronial inquiries into the Ruby Princess are ongoing and not expected to report back for at least another month.
Do you have a story tip? Email: email@example.com.