Nearly a third of the Australians quarantined in Sydney hotels who had coronavirus symptoms have tested positive for the infection.

NSW Health said on Wednesday it had tested 121 symptomatic travellers from 15 hotels – 36 (or 30 per cent) had COVID-19.

Among them are an adult and child from a family of seven who were staying at the Hilton Hotel. Three children from the family were taken to Sydney’s Royal Prince Alfred Hospital late on Tuesday, with the positive tests confirmed on Wednesday.

NSW Health said they had mild symptoms.

Video shot outside the hotel showed the children on stretchers wearing protective face masks and being wheeled out of the hotel by paramedics.

The hotel is one of those being used to quarantine thousands of travellers who have returned to Australia from overseas.

NSW Health said passengers who sat near the family on their flight back to Australia should be aware of coronavirus symptoms and call their GP if they developed any.

• See a full list of flights with known COVID-19 cases here

NSW had 227 people being treated for COVID-19 on Wednesday. That included 36 people in intensive care, 22 of them on ventilators.

Cruise ship voyages into Sydney linked to confirmed cases include: the Ovation of the Seas (docked March 18, 96 cases), Voyager of the Seas (docked March 18, 47 cases), Celebrity Solstice (docked March 19, 14 cases), the Ruby Princess (docked 19 March, 379 cases among passengers and crew).

There have been six deaths in NSW associated with the Ruby Princess, and nine more in other states.

Among them is a 62-year-old South Australian woman who became the country’s 50th coronavirus fatality on Wednesday. South Australian Premier Steven Marshall said the Ruby Princess was a “shocking situation”.

“It has caused havoc right across our nation,” Mr Marshall said.

NSW Police has started a homicide investigation into how the Ruby Princess was allowed to dock in Sydney. It eventually docked again at Port Kembla this week, with nearly 200 sick crew members on board.

Also on Wednesday, the first group of 288 Australians quarantined under strict coronavirus measures were released from the nearby Swissotel.

This group arrived in Australia from Hawaii on March 26. They had been passengers on the Norwegian Jewel cruise ship.

The group have now completed their mandatory 14-day self-isolation, to protect the community from the coronavirus.

Denise (no surname given) heads home to the Southern Highlands after 14 days in quarantine at the Swissotel. Photo: AAP

Gold Coast woman Christine Cooper said she and her husband Graham had been well looked-after during the “long two weeks”.

“It’s weirder getting out,” Ms Cooper said on Wednesday.

“You feel like an inmate that’s been in jail and now you’ve been released.”

Mr Cooper said they had been well fed at the Swissotel.

“The food was as good as you could get under the circumstances, and plentiful,” he said.

Another traveller, Rachel Deering, said hotel staff had been accommodating.

However, she said parts of the quarantine process were “inhumane”.

“There’s a lot that needs to be changed,” she told the ABC.

“We fully support the concept of quarantine but this is a very ill-conceived plan – very poorly executed.”

All in the group were to get letters confirming their isolation periods and have final health checks before leaving, under police supervision.

Police are also expected to supervise further hotel departures at the weekend, with 3000 Australian residents expected to come out of hotel isolation across the country in the next week.

“[On] Sunday, we start to see thousands of people come out of the Sydney hotels and head home. And I think that’s a wonderful thing for all of those Australians,” NSW Police Commissioner Mick Fuller said on Wednesday.

“We thank them for their patience, and really protecting the safety of the people of NSW.”

-with AAP