Embarking on the Ruby Princess cruise at the start of the COVID-19 pandemic believing the liner was free from the virus was “very stupid”, a judge has been told.

Giving evidence in the Federal Court on Monday, former nurse Susan Karpik admitted she had been extremely naive in expecting Princess Cruises to eliminate coronavirus from the Ruby Princess before the ship left Sydney on March 8, 2020.

“We had assumed there was no coronavirus on that ship when we boarded … and I recognise now it was probably very stupid now of us to have that view,” she told Justice Angus Stewart.

At the time, however, she said she expected Princess Cruises to be on top of the coronavirus situation and to either cancel the voyage if the virus was detected or at least inform passengers to give them a choice.

Mrs Karpik is the lead plaintiff in a class action against Australian charter company Carnival, which trades under the Princess Cruises name, and the operator of the Ruby Princess, Bermuda-registered Princess Cruise Lines.

She is seeking damages, alleging the cruise line failed in its duty to take reasonable care of the passengers. Her claim revolves around the illness of her husband Henry, who had to be placed in an induced four-week coma after contracting the virus, and his ongoing care.

In total, 663 positive cases were reported among the 1679 Australians on board. Twenty-eight people died from the outbreak.

The Ruby Princess sailed from Sydney for New Zealand on a 13-day round trip. It returned 11 days later, when Australia’s borders were shut in the early days of the pandemic.

Mrs Karpik told the court her husband tested positive to influenza A aboard the ship, but that he was not tested for coronavirus.

“He asked the ship’s doctor if he could be tested and she said that the tests were not available, the helicopter hadn’t dropped them off yet.”

When the ship returned to Sydney on March 19, the couple was allowed to travel home. Mr Karpik was taken to Wollongong Hospital on March 21, and intubated and placed in an induced coma the following day.

Under cross-examination by Princess Cruises’ barrister David McClure SC, Mrs Karpik said she discussed coronavirus with her doctor son-in-law before departing .

“He actually said that cruise ships from his perspective were Petri dishes and the risk of infection was high for any illness or any condition,” she told the court.

This conversation also referred to Princess Cruises’ Diamond Princess on which around 700 people became infected with the virus off Japan in February 2020.

Ms Karpik said she expected Princess Cruises to take extra steps to prevent further outbreaks after what occurred on the Diamond Princess.

The couple boarded the Ruby Princess knowing COVID-19 was highly contagious and possibly fatal, the court heard.

She said that, at the time, she knew the virus was circulating in the northern hemisphere but was not aware that over 70 Australians had contracted it and that two had died.

Mrs Karpik expected Princess Cruises to be “100 per cent cautious” about the screening of staff coming in from across the globe.

“We might have been terribly mistaken, but we felt that the cruise company had an obligation to us as customers that that screening would happen.”

She felt reassured about measures taken by the cruise line, including barring those who had travelled to China, Macau or Hong Kong from embarking.

Questioned by Mr McClure, Mrs Karpik admitted there was a risk of contracting COVID-19 on the ship.

“Probably much the same as if we were shopping in a busy shopping centre or whatever. The risk is always there.”

However, she later backtracked on this statement, saying she was confused and thought the questioning was about influenza or gastro. She stressed she had not seen any risk of catching coronavirus aboard before the trip.

The hearing continues.

-AAP