Health authorities in NSW have confirmed 83 new coronavirus infections in the 24 hours to 8:00pm on Friday.

Key points: NSW Health has banned travel to Lord Howe Island

NSW Health has banned travel to Lord Howe Island Four cruise ships have experienced cases of COVID-19 in relation to travel out of Sydney

Four cruise ships have experienced cases of COVID-19 in relation to travel out of Sydney A religious service attended by 300 people on March 8 in Ryde has resulted in seven cases

The new cases take the state's total number of COVID-19 infections to 436 and represent NSW's largest increase over a 24-hour period.

A total of 46,456 people have been tested and cleared in NSW.

Out of the 436 cases, 218 were picked up overseas, 92 have been cases caught from a contact and 74 have been diagnosed as locally acquired, but with an unidentified contact.

The remainder are being investigated.

NSW Health has also declared a ban on travel to Lord Howe Island from 5:00am on Sunday in a bid to restrict the spread of the virus.

The ban means access to Lord Howe Island is restricted to residents, health workers and other essential service workers.

Any new arrivals within permitted categories will be subjected to a 14-day quarantine.

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NSW Health Minister Brad Hazzard encouraged people to heed advice on social distancing, amid the rising number of infections.

"The problem is just over the horizon on the basis of the numbers that we're now seeing," he said.

"Particularly here in New South Wales, they are showing a substantial increase.

"We will all remember the numbers in the last few days, they've effectively doubled just in the last week.

"Save yourself and save your family. Listen to the messages that are coming out, not just from Government officials but from doctors."

Elsewhere, seven people have been confirmed as COVID-19 cases after attending a church service with a congregation of more than 300 people.

The Sydney Church of Christ service took place at Ryde Civic Centre on March 8.

Close contacts of cases have been put into self-isolation and NSW Health is warning attendees of the service to be alert for symptoms.

Yesterday, Mr Hazzard revealed several people on board the Ruby Princess cruise ship, which docked in Sydney earlier in the week, had tested positive to coronavirus.

He warned the 2,700 passengers that disembarked they could have been exposed to COVID-19, and urged them to self-isolate for 14 days.

Today, NSW Health named three other cruise ships which have had confirmed COVID-19 cases onboard.

A 67-year-old passenger has been diagnosed after travelling on the Ovation of the Seas out of Sydney.

The ship is now at sea with only crew on board.

A woman in her 20s has been diagnosed with COVID-19 after travelling on the Voyager of the Seas, which returned to Sydney from New Zealand on March 7.

On a later trip on the Voyager of the Seas, a 66-year-old man was confirmed as having COVID-19.

The other case involves a passenger on the Celebrity Solstice, who travelled on the cruise ship before it docked in Sydney on March 20.

The Ruby Princess remains at sea between Sydney and Wollongong after recording four confirmed cases of COVID-19.