The Pacific Dawn cruise ship will be quarantined for a second time after several crew members began displaying flu-like symptoms.
The ship, which docked in Sydney on Monday with a number of sick passengers, has since taken on more holidaymakers and headed towards the Great Barrier Reef.
It will now bypass a number of planned stops before anchoring at Willis Island, east of Cairns, where it will enter quarantine.
(Read more: Ship again hit by swine flu scare)
The latest confirmed case comes as news that as many as one in five Australians may contract the rapidly-spreading flu, with a McDonalds franchise the latest to be hit.
A restaurant at Epping Plaza in Melbourne's northeast has closed after one of its staff became ill with the virus, another confirmed case in a national total now exceeding 60.
The fast-food chain said it was informing other employees at the outlet, which would stay closed as a "precautionary measure" while health checks were carried out.
McDonalds regional manager Stephen Shillington told AAP the restaurant would reopen on Thursday while Epping Plaza management confirmed the mall would remain open after receiving the all-clear.
As the national total of confirmed cases doubled in the past 24 hours, Victoria's acting chief medical officer Rosemary Lester said up to 20 percent of the population could contract the potentially deadly virus over the coming year.
"We have seen this pattern in countries such as the US, Canada and Japan, so next year this may well be the predominant virus,'' she said.
"We would expect that this virus will become one of the seasonal circulating viruses."
Victoria is the worst-hit state with 32 confirmed cases after eight more people were diagnosed with the strain overnight, with the infection penetrating Melbourne's eastern suburbs for the first time.
In NSW, the entire state cabinet has been caught up in a swine flu scare after it emerged Tourism Minister Jodi McKay travelled on a flu-affected flight, then met with colleagues. (Read more: Threat to NSW cabinet)
Federal Health Minister Nicola Roxon appealed for calm over the outbreak, but warned she expected the number of confirmed cases to rise sharply in the coming days.
She said a vaccine was in the early stages of development, a complicated process which would probably take some months.
"It's why every week that we can delay this disease spreading more widely in the community is buying us more time when we'll have this vaccine to treat it," she said. (Read more: Vaccine 'months away')
Professor Terry Nolan, head of population health at the University of Melbourne, said a vaccine would take time because the virus first had to be grown in a laboratory from an existing sample.
"The vaccines take about three months, perhaps a bit longer, depending on testing," he told ninemsn.
"If the virus is in full circulation, authorities may weigh up the risk versus reward of the testing [and release the vaccine immediately]."
Meanwhile, the Australian Tourism Council has attacked politicians and the media for provoking "hysteria" over the swine flu outbreak. (Read more: Appeal to end 'overreaction')
The council's managing director Matthew Hingerty said businesses were already feeling the pinch as overseas tourists expressed reluctance to come to Australia.
Last night anger mounted over the decision to allow passengers aboard the cruise ship Pacific Dawn to disembark in Sydney, despite dozens of them either reporting flu-like symptoms or saying they had been in contact with people with symptoms. (Read more: Passenger slams 'irresponsible' decision)
But the public should remember that Australian cases of the virus at this stage appeared to be very mild, former University of Adelaide virology professor Chris Burrell said.
"It's looking at the moment that the virulence is no greater than the seasonal flu viruses we get each winter," he told ninemsn.
"But it's a completely new virus and it's spreading very easily … the whole world is like a virgin population."
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