A cruise ship that is the subject of a criminal investigation after it became Australia’s largest single source of coronavirus infections set off from Australian shores Thursday a month after it was ordered by police to leave.

The Ruby Princess has been linked to 19 deaths in Australia and two in the United States. Australia has recorded 75 COVID-19 deaths. A government inquiry is underway into why 2,700 passengers and crew were allowed to disembark in Sydney on March 19 before the results of swabs of sick passengers were known.

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The cruise ship Ruby Princess is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

A cruise ship that is the subject of a criminal investigation after it became Australia’s largest single source of coronavirus infections set off from Australian shores Thursday a month after it was ordered by police to leave.

A person, bottom right, looks over the balcony of a cabin on the cruise ship Ruby Princess that is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

New South Wales state banned further cruise ship arrivals until new health protocols are agreed with the federal government.

The Ruby Princess gets a water canon salute as it departs from Port Kembla in Wollongong, Australia, Thursday, April 23, 2020. The ocean liner became notorious as Australia's largest single source of coronavirus infections and is the center of a criminal investigation over the sickness' spread set off a month after it was ordered by police to leave. (AP PhotoRick Rycroft)

A large banner strung across its stern said: “Thank You Illawarra,” referring to the coastal region around the port.

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

One of the 550 crew members on board sent an email to Australian Broadcasting Corp. saying she had no choice but remain with the ship.

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

State police are investigating whether Ruby Princess’ management downplayed potential COVID-19 cases before passengers disembarked.

Many passengers flew from Sydney overseas. Two died at home in the United States, including 64-year-old Los Angeles resident Chung Chen, whose family is suing Princess Cruises for more than $1 million for failing to alert passengers to the risk. Princess Cruises is a subsidiary of Carnival Corp., which is incorporated in Bermuda and headquartered in California.

The cruise ship Ruby Princess is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

The cruise ship Ruby Princess is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

New South Wales state banned further cruise ship arrivals until new health protocols are agreed with the federal government.

The Ruby Princess delayed its departure from Port Kembla, south of Sydney, because of sickness among crew members, several of whom have died in Sydney hospitals.

It left the cargo port with a skeleton crew late in the afternoon nudged by two tug boats.

A person, bottom right, looks over the balcony of a cabin on the cruise ship Ruby Princess that is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

A person, bottom right, looks over the balcony of a cabin on the cruise ship Ruby Princess that is docked at Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

A large banner strung across its stern said: “Thank You Illawarra,” referring to the coastal region around the port.

Princess Cruises did not immediately disclose where the ship was heading. Media have reported its destination is the Philippines.

On Thursday morning, 300 Filipino crew left the ship and were taken to Sydney to catch a charter flight to Manila. They traveled from Port Kembla in 40 buses necessitated by social distancing rules.

The Ruby Princess gets a water canon salute as it departs from Port Kembla in Wollongong, Australia, Thursday, April 23, 2020. The ocean liner became notorious as Australia's largest single source of coronavirus infections and is the center of a criminal investigation over the sickness' spread set off a month after it was ordered by police to leave. (AP PhotoRick Rycroft)

The Ruby Princess gets a water canon salute as it departs from Port Kembla in Wollongong, Australia, Thursday, April 23, 2020. The ocean liner became notorious as Australia's largest single source of coronavirus infections and is the center of a criminal investigation over the sickness' spread set off a month after it was ordered by police to leave. (AP PhotoRick Rycroft)

One of the 550 crew members on board sent an email to Australian Broadcasting Corp. saying she had no choice but remain with the ship.

“We have been given no option to leave we have to stay on board. Myself and my family are worried and scared of what will happen next,” the email said. ABC did not identify the author.

Health authorities said everyone who remained on board had been cleared of the virus.

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

State police are investigating whether Ruby Princess’ management downplayed potential COVID-19 cases before passengers disembarked.

Police ordered all foreign cruise ships to leave the state in late March, fearful that sick crews could overwhelm Sydney hospitals.

Ruby Princess refused for fear of a COVID-19 emergency in the open ocean.

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

Crew from the cruise ship Ruby Princess are bussed from Port Kembla as authorities prepare for the ship's departure in Wollongong, Thursday, April 23, 2020. The Ruby Princess has been ordered to leave Australia after disembarking passengers in Sydney in March that have tested positive for COVID-19. (AP PhotoRick Rycroft)

The ship’s doctor Ilse Von Watzdorf told the first day of a New South Wales government inquiry into the debacle on Wednesday that she was surprised health authorities had allowed passengers to leave in Sydney before the test results were known.

Von Watzdorf gave evidence to the inquiry by video-link from the ship where she has been in quarantine.

The ship had returned to Sydney after an 11-day cruise to New Zealand, which was regarded as a low-risk destination.