The Norwegian Dawn had been scheduled to dock in Port Louis on Sunday, but since it had not gone to Reunion Island, it arrived in Port Louis a day earlier, the Mauritius Ports Authority said in a statement.

"The decision not to allow the cruise ship access to the quay was taken in order to avoid any health risks," the authority said.

"The health and safety of passengers as well as that of the country as a whole are of the utmost to the authorities."

The port authority did not give any more details on the nature of the health risk, and said their test results will be known in 48 hours.

Officials at the health ministry were not immediately reachable for comment.

The U.S.-headquartered Norwegian Cruise Line did not immediately respond to an email request for comment.

The ship has 2,184 passengers and 1,026 crew members. Of these, about 2,000 passengers would have disembarked in Port Louis after completing their cruise while another 2,279 new passengers had been expected to board the ship, the port authority said.

"Passengers who were due to board the 'Norwegian Dawn' and begin their cruise from Mauritius today will not be able to do so due to potential health risks," it said.

Tourism is one of the major drivers of Mauritius' economy.

(Reporting by Villen Anganan; Writing by George Obulutsa, editing by Emelia Sithole-Matarise)