SYDNEY - Australia's New South Wales Health Minister Brad Hazzard said on Friday that three people among the 4,000 passengers and crew onboard a cruise ship were tested positive for COVID-19.

Hazzard told reporters that doctors did 13 tests on board the "Ruby Princess" which docked in Sydney and found three COVID-19 cases, including one crew member.

Some 2,700 passengers left the ship when the testing were still conducting. Those passengers had been asked to leave their contact details before they disembarked on Thursday. Hazzard urged them to self-quarantine for 14 days.

"Our big concern is that those people came off the cruise with no knowledge of COVID being on the ship, and if they think it's OK to be wandering around, the clear message from me as NSW health minister is: No, it's not, put yourself immediately into quarantine," Hazzard said.

"Put yourself in a self-isolation. Follow the rules, and if you're feeling ill, any of the symptoms that might be related to COVID-19, then make sure you contact a medical practitioner, either your local GP or the local ED in the hospital, and then take advice on what you should be doing."

Hazzard also told reporters on Friday that the COVID-19 cases in New South Wales had reached 382, with 75 new cases overnight, which was the biggest single day increase in the state.