A statement from Princess Cruises initially said 10 people tested positive for the virus, but none were Canadian.
Later on Wednesday, health workers in the port city of Yokohama, said 10 more people were confirmed sickened with the virus and they will be transferred to nearby hospitals for further testing and treatment.
The cruise line says the first 10 infected cases included two Australians, three Japanese, three people from Hong Kong, and one from the United States, as well as a Filipino crew member.
Foreign Affairs Minister Francois-Philippe Champagne says the Canadian mission in Tokyo has been in touch with the Canadian passengers on the ship to offer them consular assistance, and the government will look to the cruise line to repatriate them when the quarantine is finished.
Covered from head-to-knee by large, white sheets, the positive cases were led by gloved and masked officials onto Coast Guard vessels, to be taken ashore and transported to local hospitals.
The ship will remain under quarantine for 14 days in Yokohama, Princess Cruises says.
The cruise line says it will continue to fully co-operate with and follow the instructions of global medical authorities and the Japanese government.
It says it will also be cancelling the next two Diamond Princess cruises departing Yokohama on Feb. 4 and 12.
The viral outbreak that began in China has infected more than 24,500 people globally with 490 deaths reported in the Hubei province, the epicentre of the disease.
More than 1,800 people on another cruise ship were being screened in Hong Kong after three passengers on a previous voyage were diagnosed with the virus.
— With files from the Associated Press