The NSW government is under fire over its handling of the liner. Test results released by the government on March 20 showed four passengers had contracted the virus while on-board but, by that time, 2647 people had left the ship.
News.com.au has contacted Carnival Australia for comment.
The announcement of the criminal investigation comes after a string of leaked phone calls between the Port Authority of NSW and senior Carnival Australia cruise company officials might have led to a snap decision to allow the Ruby Princess to dock in Sydney on March 19.
According to records obtained by the Sunday Telegraph, several phone calls took place on the evening of March 18 and in the early hours of March 19, just hours before the "death ship" docked.
According to the newspaper, Port Authority officials had initially denied the ship permission to dock after they were made aware that some passengers on board had Covid-19 symptoms.
A representative from the Ruby Princess contacted Ambulance NSW to book two vehicles for patients they believed had coronavirus and had allegedly been tested.
That information was passed on to the NSW Port Authority, who decided to deny the ship entry to Sydney Harbour.
However, after receiving a call about midnight from Carnival Australia authorities, the newspaper alleges the Port Authority backflipped on its decision, allowing the ship to dock.
According to the Port Authority logs, obtained by the Sunday Telegraph, it is claimed ambulance vehicles were called to the port to transfer three passengers with complications unrelated to the virus.
While it was the Port Authority that allowed the ship to dock, the decision to have passengers disembark was under the watch of NSW Health.
News.com.au has contacted the NSW Port Authority for comment.
On Saturday, the NSW Labor Party called for the state's Health Minister, Brad Hazzard, to resign over the Ruby Princess scandal, with the Opposition labelling it "one of the greatest health disasters" in NSW history.
"The buck stops with the Health Minister and we are today calling for the health minister to stand aside," Opposition Leader Jodi McKay said in a statement.
However, Hazzard defended the government's actions, saying the experts who made the decision were the "best in the world".
"Each of the staff of the chief health officer, who made the decision, made it to the best of their ability. And those people are experts in their field," Hazzard said.
NSW chief health officer Dr Kerry Chant said if they had known coronavirus was on board the ship, they would have disembarked the passengers differently and moved them to self-isolation.
But she said that would have prevented only 11 cases of the virus.
"The people that have acquired their infection on the cruise ship could not have been avoided and, every period of time that people were on that cruise ship, there were actually at risk of more transmission on the cruise ship in a very, vulnerable age group," Chant said.
According to the Sun-Herald, the Ruby Princess had logged 128 ill passengers and crew on board, with 24 of those having a fever over 38 degrees.
The report, obtained by the publication, allegedly shows a further six people reported muscle aches, diarrhoea, severe headaches or vomiting.
The publication claims instead of asking passengers whether they had travelled to a variety of countries considered to be medium or high risk, it is understood those on board were only asked to specify if they'd travelled through mainland China or Iran or transited through South Korea. However, at the time the ship was allowed to dock in Sydney, Cambodia, Hong Kong, Indonesia, Japan, Singapore and Thailand had been listed by the Department of Foreign Affairs and Trade as moderate to high risk.
NSW Police Commissioner Mick Fuller is investigating the handling of the saga.
