Sydney, Apr 5 (IANS): Australian authorities on Sunday launched a criminal probe into how passengers of a cruise ship were allowed to disembark in Sydney despite some exhibiting flu-like symptoms.

More than 600 people on board the Ruby Princess later tested positive for coronavirus and 10 have since died. The ship remains off the coast with nearly 200 sick crew members on board, the BBC said in a report.

At a news conference here on sunday, New South Wales (NSW) Police Commissioner Mick 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," the BBC report quoted Fuller as saying.

He said that the day before passengers disembarked in Sydney, a worker made an emergency call about two people who needed medical assistance.

He said police were assured by the operating company that the coronavirus was not an issue on the ship.

"From that perspective, there are many unanswered questions," he added.

The Ruby Princess with about 2,700 people on board arrived in Sydney last month after an 11-day cruise.

Australia has so far reported 5,548 coronavirus cases and 30 deaths.

Those who fell ill on cruise ships account for nearly a tenth of all cases in Australia.