Thousands in lockdown on cruise ship in Japan as 61 passengers test positive to coronavirus_1

Thousands of passengers remain quarantined on the Diamond Princess cruise ship as 41 new cases of the novel coronavirus have been confirmed.

Twenty people, including two Australians, on the ship have already tested positive as having the novel coronavirus, as the rest of the 3700 passengers and crew wait to see if symptoms develop.

The ABC reported a total of 170 people have been tested in the past few days, describing it as a "significant development" with the number of passengers who tested positive to coronavirus hitting 61 on Friday afternoon.

Health authorities in Japan removed 10 passengers from the ship on Thursday to various prefectures across Yokohama, with that number doubling to 20 and as of 12pm on Friday there were 61 confirmed cases.

There are 200 Australians on board the ship.

Related: What passengers should know about the coronavirus

Confined passengers took to social media to report conditions on board the cruise liner, including Queensland couple Paul and Jacqui Fidrmuc who said it was a "frightening situation".

They were among 170 tested and will be forced to spend 12 more days in quarantine. They passed their medical testing but are concerned they still might have the virus.

"The concern we have is we might have the virus and we don't have the symptoms," Mr Fidrmuc said on Thursday.

"It's a frightening situation but it is not a disease where if you get it, it's certain death. You just have to be lighthearted about the whole situation."

The website for Diamond Princess issued an updated health advisory for its passengers, with many scheduled cruises being cancelled, delayed or diverted to other ports.

-with AAP