Fuller announced the move as it was revealed four more passengers from the doomed ship had died – bringing the total to 11, and accounting for more than 30 per cent of all Australian coronavirus deaths.

The Ruby Princess has been widely criticised since its 2700 passengers were allowed to freely disembark in Sydney on March 19, despite passengers on board showing signs of respiratory illnesses, and some being transported to hospital with symptoms of the virus.

The ship has since proven to be a hotbed of infection.

At least 662 people linked to the cruise have been diagnosed with coronavirus, more than 10 per cent of Australia’s total cases.

In a press conference on Sunday, Fuller said there were “many unanswered questions” about the incident.

He said that, by law, vessels were only allowed to dock and disembark passengers if the captain could assure the local authorities that their ship was free from contagious disease.

Fuller said there were “discrepancies” involving the information provided by the ship’s owners, Carnival Australia, and the requirements of the law.

“The only way I can get to the bottom of whether our national biosecurity laws and our state laws were broken is through a criminal investigation,” he said.

“The key question that remains unanswered … was Carnival transparent in contextualising the true patient and crew health conditions relevant to Covid-19?

“There seems to be absolute discrepancies between the information provided by Carnival and what I would see is the benchmark for the laws that the federal government and the state government put in place in terms of protecting Australians from cruise ships when coronavirus had started.”

The investigation will involve interviewing thousands of witnesses, including the Ruby Princess’ captain and doctors, the crew and passengers; and staff from various Commonwealth and NSW Government offices and agencies.

Fuller also praised the NSW Port Authority for their efforts the night before the ship docked.

“The New South Wales Port Authority did an exceptional job in trying to get to the bottom of the facts in relation to this case,” he said.

“They made contact with the ship on numerous occasions.

“They actually stopped the ship from coming into Sydney harbour without further medical information, they made contact with operations manager from Carnival.

“And on each case they were informed that Covid-19 wasn’t an issue on the ship.”

Fuller did not rule out the possibility of criminal negligence charges being laid in relations to the case.

He also confirmed around 200 crew members on board are currently showing symptoms of coronavirus, as medical officers continue to conduct testing.

The Ruby Princess remains in Australian waters, treating crew members in their medical facilities, and delivering those who require additional medical care to shore.

While it appears that the Ruby Princess will not be asked to leave Australian waters in the near future, there is still a concern for the crews of five other cruise ships that departed Australian waters over the weekend.

These include the Celebrity Solstice, Voyager, Ovation, Spectrum and Radiance of the Seas.