More than a thousand people have now tested positive to coronavirus in Australia.

New South Wales reported 83 new cases on Saturday, its biggest one-day jump to date, bringing the total number of infections in the state to 436.

Seven of the new cases were identified in people who attended a church service at Sydney's Ryde Civic Centre on 8 March alongside more than 300 others.

Positive COVID-19 cases have also been detected on four more cruise ships to have docked in Australia.

Those cases are in addition to the four people who tested positive on the Ruby Princess ship, from which passengers were allowed to disembark in Sydney on Friday.

The new ships affected include the Ovation of the Seas, the Voyager of the Seas and the Celebrity Solstice.

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A 67-year-old man tested positive for the virus after travelling from Canada and boarding the Ovation of the Seas ship, which departed Sydney on 11 March and returned on 18 March. There is no evidence of an outbreak on the ship, NSW Health said.

The second case was identified in a woman in her 20s who travelled on the Voyager of the Seas cruise from Sydney, departing on 25 February, and stopped in the South Pacific and New Zealand, before returning to Sydney on 7 March. Again, NSW Health said there was no evidence of a more extensive outbreak.

A 66-year-old male passenger on a later voyage of the same ship, which visited islands in the South Pacific, has also tested positive and is being treated in a Sydney hospital. Passengers of this cruise are being urged to self-quarantine for 14 days in line with requirements for all cruise ship passengers.

The final case was in a male passenger from New Zealand who joined the Celebrity Solstice cruise in Auckland on 10 March and disembarked in Dunedin on 15 March. The ship then continued on to Sydney, where it docked on 20 March.

"It is very, very bad overseas ... but the problem is just over the horizon on the basis of the numbers that we are now seeing, particularly here in NSW where they are showing a substantial increase," NSW Health Minister Brad Hazzard said on Saturday afternoon.

"Save yourself and save your family, listen to the messages that are coming out."

NSW Health has also announced an immediate ban on travel to Lord Howe Island, located 600 kilometres off the coast of Port Macquarie, to stop the virus from spreading to the remote community.

Residents and essential service workers will still be allowed access to the island but will have to undertake a 14-day quarantine on arrival.

Cases jump around the country

Earlier on Saturday, Victorian Premier Daniel Andrews announced 51 new cases in his state, bringing the total number of cases there to 229.

Queensland authorities also reported 37 new positive tests, bringing the state total to 221, while Western Australia recorded 26 new cases, taking its total to 90. South Australia's total jumped by 17 to 67.

It was also confirmed on Saturday the number of confirmed cases in the Northern Territory had increased from three to five.

Shortly after, Chief Minister Michael Gunner announced anyone arriving from overseas or interstate would have to self-isolate for 14 days from 24 March.

"The Territory comes first," he said.

The new measures will start from 4.00pm on Tuesday with strict border controls for all access points – by road, rail, air and sea. People who arrive in the NT from interstate will be required to quarantine for 14 days. — Aneeta Bhole (@AneetaBhole) March 21, 2020

Seven people have so far died in Australia after contracting the virus; six in NSW and one in Western Australia.

More than 272,000 cases have so far been confirmed across the world. Of these, approximately 87,000 have recovered and more than 11,000 have died.

Coronavirus symptoms can range from mild illness to pneumonia, according to the Federal Government's website, and can include a fever, coughing, sore throat, fatigue and shortness of breath.

As of Saturday morning, only people who have recently travelled from overseas or have been in contact with a confirmed COVID-19 case and experienced symptoms within 14 days are advised to be tested.

If you believe you may have contracted the virus, call your doctor, don’t visit, or contact the national Coronavirus Health Information Hotline on 1800 020 080.

If you are struggling to breathe or experiencing a medical emergency, call 000.