At least 61 people on board a cruise ship off the coast of Japan have tested positive for coronavirus, the country's government said on Friday. Thousands of passengers and crew on the Diamond Princess could be quarantined for up to two weeks to prevent further infections. Twenty people who earlier tested positive for coronavirus, which has infected more than 30,000 people in China, have been removed from the cruise liner. Japanese authorities have so far tested 273 people on board, with an additional 41 cases diagnosed. "The results of the remaining 171 tests came out and 41 tested positive," Health Minister Katsunobu Kato told reporters. "Today they will be sent to hospitals in several prefectures, and we are now preparing for that." Passengers on the ship have been asked to stay in their cabins. British man Alan Steele, 58, is among one of the newly-diagnosed passengers, Press Association reported on Friday. Mr Steele posted on Facebook: “Just to let you all know I have been diagnosed as having the virus and am being shipped to hospital. “Would also like to say that at the moment I am not showing any symptoms so just possible a carrier. “Will let you know how I am going on when possible.” Fellow British passenger David Abel said the separation would be “really tough” for Mr Steele, who was on honeymoon with his wife, Wendy. "He will be going off in to quarantine in a medical facility and she has to stay on board the ship because she's not displaying symptoms,” Mr Abel said in a Facebook video. "That's going to be really, really tough for him so just bear a thought for these passengers who just don't know what is going to be lying ahead of them." The Diamond Princess, which arrived off Japan’s coast on Monday evening, has more than 3,700 passengers and crew on board. The ship docked in Yokohama on Thursday to resupply for a quarantine that could last until February 19.