The companies operating the Ruby Princess cruise ship have rejected allegations they were responsible for the 2020 COVID-19 outbreak that led to the deaths of 28 people.

Charterer Carnival and ship owner Princess Cruise Lines are facing a class action in the Federal Court over the outbreak.

David McLure SC, for the companies, told Justice Angus Stewart there were no requirements from the Australian government for the line to screen passengers and that international travel restrictions had not been introduced by March 8, 2020 when the cruise departed Sydney for New Zealand with 2641 passengers.

Of the 1679 Australians, 663 are believed to have caught COVID.

The ship eventually turned around because of the number of cases and was the centre of bizarre scenes when it finally docked back in Sydney, on March 19.

Crew lined the gangway as passengers – some seen coughing and spluttering – left the ship, catching trains, buses and even overseas flights to get home.

But in his opening, Mr McLure said there was also no requirement from NSW Health to have enough masks for everyone aboard when the Ruby Princess sailed.

At the time COVID was presenting as a mild disease in most cases and there was no evidence to support airborne spread. There were just 80,000 cases worldwide, he said.

He rejected the notion that the companies could protect people from a communicable disease.

“Even if all the precautions had been taken, all of those precautions would not have been capable of eliminating the virus from the cruise ship or any other environment,” he said.

If it was possible, he said, that duty of care would apply to all premises for all diseases.

“Humans are prepared to take risks,” he said.

Mr McLure also rejected that cruise ships were particularly susceptible to disease outbreaks like COVID.

He said there were many places on the Ruby Princess where people could self-isolate, taking Justice Stewart through videos and floor plans showing the many spaces on the ship.

“It’s not correct to say when a person is on a cruise ship they are then removed from the ability to take themselves out of any particular setting where they feel uncomfortable,” he said.

“As Your Honour saw from the video, at least one thing someone could do if they chose to, is go on a cruise ship and isolate themselves.”

Earlier Ian Pike SC, for the lead plaintiff, Susan Karpik, said the companies had failed in their duty of care to the passengers.

He said the companies knew of the risks COVID presented, had other ships where deaths had occurred, and did not have enough masks for the passengers and crew.

He said the cruise should have been cancelled.

“What occurred was not an accident,” he said.

Mr Pike said two sister ships had suffered outbreaks – including 700 cases and seven deaths on the Diamond Princess which had sailed out of Japan – in the weeks beforehand.

The Ruby Princess also had an outbreak in its prior cruise, which had docked in Sydney on the morning of March 8 with dozens of passengers reporting symptoms.

As a result, he said the Ruby Princess had insufficient medical supplies to combat an outbreak.

Crew had even failed to obtain enough masks, because of a global shortage, and ran out a day into the cruise.

“This boat never should have sailed,” he said.

“It was negligent to do so.”

Mr Pike said passengers were not protected during the cruise, with no social distancing, activities continuing as normal, and very little in the way of effective quarantining.

“Very few people, if any, remained in quarantine for any more than a couple of days.”

Mrs Karpik, who joined the cruise with her husband of 50 years Henry, went on to develop COVID.

Mr Karpik spent four weeks in an induced coma and still suffers several debilitating conditions, requiring constant care from his wife.

The case is expected to last at least four weeks.

-AAP