When COVID-infected passengers were allowed to disembark the now-infamous Ruby Princess cruise ship in Sydney the errors were inexcusable and inexplicable and the results deadly.
A special commission of inquiry into the ship's arrival in Sydney on March 19 has determined authorities made a litany of mistakes when contagious travellers alighted at Circular Quay, spreading the virus across Australia and overseas.
Drawing on three weeks of hearings, the Special Commission of Inquiry commissioned by the NSW government released its findings on Friday.
In the scathing 330-page report, eminent barrister Bret Walker SC - who led the inquiry - reserved his harshest criticism for NSW Health while absolving Australian Border Force officials of blame.
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.
Notifying the Ruby Princess of the change would have identified such suspect cases, as 101 people fell under the definition by 18 March and later 120 when the ship docked.
Those people should then have been isolated in cabins, the inquiry found.
The Ruby Princess outbreak infected 663 Australians on board and led to 28 deaths, including 20 domestically and eight in the United States.
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.
Passengers disembarked before the results of 13 expedited tests showing at least three people had the virus.
The delay was "inexcusable" and the swabs should have been tested immediately, Mr Walker said.
Instead, 2700 passengers left the ship as it had been deemed low risk by health officials as only 0.94 per cent had reported flu-like symptoms and none had visited virus-hit nations China, Italy, Iran or South Korea.
The one per cent threshold required to mandate NSW Health intervention had "limited" utility for assessing if COVID-19 was circulating onboard, the commission found.
"In light of all the information the (NSW Health) Expert Panel had, the decision to assess the risk as 'low risk' - meaning, in effect, 'do nothing' - is as inexplicable as it is unjustifiable," the report said.
The NSW government then erred by allowing disembarked passengers to immediately travel interstate and abroad, breaching the state's public health order that came into effect two days earlier.
By the time NSW Health corrected the advice on March 21, the inquiry said it was "too late" as many passengers - including some symptomatic ones - were already in transit.
"Ultimately, every passenger and crew member of the Ruby Princess should have been tested for COVID-19 while in enforced quarantine," the inquiry said.
"Those who tested negative could then have been released, at appropriate times."
The ABF did not play any part in the mishap, Mr Walker said, given border officials' lack of medical or epidemiological expertise.
Reflecting on the "sorry episode", Mr Walker said it would be unhelpful to make recommendations as they essentially amounted to "do your job".
"There are no 'systemic' failures to address," the commissioner wrote.
"Put simply, despite the best efforts of all, some serious mistakes were made."
NSW Premier Gladys Berejiklian said she would read the report over the weekend and respond early next week.
State opposition leader Jodi McKay urged the premier to own up to the failings and apologise.
Princess Cruises said the report confirmed none of its staff misled public authorities who oversaw the vessel's disembarkation.
Separate NSW Police and coronial inquiries into the Ruby Princess are ongoing and not expected to report back for at least another month.
Australian Associated Press