A total of 33 crew members on have tested positive for the coronavirus on a Costa Crociere cruiseship after it underwent repairs at a Mitsubishi Heavy Industries (MHI) shipyard.

The outbreak occurred on the Carnival Corp subsidiary's 2,114-berth Costa Atlantica (built 2000) while it was at the Koyagi shipyard in Nagasaki. Around 623 crew members in total were stationed onboard as the ship as it underwent repairs.

Although the crew members were supposed to be confined to the ship, it is suspected that some went ashore and there is some concern the infection may have spread. The vessel is currently alongside at the Koyagi yard.

The Costa Atlantica was one of three Costa Crociere ships booked in for repair at the the Nagasaki-based facility in February and March this year.

The other two were the 4,200-berth Costa Venezia (built 2019) and the 3,000-berth Costa Serena (built 2000).

The ships were booked in at Nagasaki because Costa Crociere's favoured Chinese repair yards were closed down because of an earlier outbreak of Covid-19 infections in the country.

Mitsubishi had plans to turn its Nagasaki yard into a cruiseship repair yard and saw the Costa Crociere repair order as a breakthrough.

At the time it won the deal it said it would take every precaution to ensure safety and stop the spread of coronavirus.

'Priority issue

“Prevention of Covid-19 virus infection has been the highest priority issue among Costa, Mitsubishi and the relevant Japanese authorities,” MHI said when it won the contract.

It added that all crew had been tested to insure that there were no Covid-19 infections onboard.

MHI said: “All three vessels were legitimately quarantined by the local quarantine branch when entering Japan, and the repairs and maintenance works are carried out under the strict control of the infection prevention procedures of both Costa and Mitsubishi.”

The Costa Atlantica incident is the second time there has been an outbreak of Covid-19 infections on a cruiseship in Japanese waters.

In March more than 700 passengers and crew became infected when the 115,900-gt Diamond Princess (built 2004) was held in quarantine at the port of Yokohama.

News of the outbreak comes just a week after Japanese Prime Ninister Shinzo Abe put the country into lockdown to prevent the spread of coronavirus.