New South Wales has recorded four more COVID-19 deaths, including three former passengers on the coronavirus-stricken Ruby Princess cruise ship.

Key points: There have now been 10 deaths and more than 600 cases connected to the Ruby Princess cruise ship

There have now been 10 deaths and more than 600 cases connected to the Ruby Princess cruise ship The three latest deaths were all elderly male passengers on the ship

The three latest deaths were all elderly male passengers on the ship The NSW Government has defended its handling of the Ruby Princess disembarkation

The four victims were all older men.

Their deaths take the state's COVID-19 toll to 16.

Of the three passengers who travelled on the Ruby Princess, a 91-year-old died at Port Macquarie Base Hospital.

The other two men were aged 76 and 80 and died at Westmead Hospital.

The fourth man, aged 61, died at Hornsby Hospital. No details have been given about how he contracted the virus.

Eleven people who were on the Ruby Princess, which docked in Sydney on March 19, have now died from COVID-19.

The ship, which had 2,647 passengers and 1,148 crew, has had 600 confirmed cases of COVID-19, 342 of which are in NSW.

There have been no deaths among 11 cases of secondary transmission from the cruise ship.

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Passengers were given the green light by NSW Health to depart the ship in March, despite receiving reports that multiple people on board had experienced flu-like symptoms.

Dr McAnulty said his condolences went out to the men's families.

"It just reinforces that message that the elderly and people with underlying diseases are most prone to severe complications, intensive care and death," he said.

NSW Police are probing the handling of the coronavirus-affected cruise ship.

NSW Health Minister Brad Hazzard has strongly defended the handling of the Ruby Princess disembarkation.

"I have concern, as I said yesterday, that those who are our brightest and our finest and our most committed public health officials are in some way being diminished or criticised," he said.

"I think that they have done their best."

The ship remains off the coast of Sydney, while some 250 crew members await test results for COVID-19.

Five other cruise ships, including at least three which have had multiple COVID-cases, were refuelled and restocked in a huge NSW Police operation in Sydney over the weekend, allowing them to leave Australian waters.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 26 seconds 1 m 26 s Five cruise ships have been moved out of Sydney Harbour overnight.

The Celebrity Solstice, Voyager of the Seas and Ovation of the Seas all departed during the night, following the Spectrum of the Seas and Radiance of the Seas which left on Saturday afternoon.

Federal Attorney-General Christian Porter weighed into the Ruby Princess issue from Canberra on Sunday, saying he supported Australian Border Force commissioner Michael Outram's comments the NSW Health was to blame for the debacle.

"I found Mike Outram's explanation of the timing of events and the burying of responsibility to be utterly persuasive, so anyone who wants an answer as to responsibility for what occurred I think would would do no better than listening to Mike Outram's overview," he said.

The deaths came as NSW recorded 87 new cases of coronavirus in the 24 hours to 8:00pm on Saturday, taking the statewide total to 2,580.

Of that total, 1,566 cases were acquired overseas.

NSW Health said the rate of increase of COVID-19 cases over the past fortnight had fallen from about 25 per cent to 4 per cent.

However, the authority warned it was soon to tell whether the trend would continue.