Carnival Corp has received a Covid-19 safety credential for one of its nine brands but is not quite ready to pull up anchor on its entire fleet of 90 ships.

Costa Cruises has received a Biosafety Trust Certification from cruiseship classification society Rina that tests "all aspects of life onboard and ashore", the Arnold Donald-led cruise major said.

The certificate signed off on several areas of the vessels' operations, including embarkation procedures, hotel services, catering, fitness, relaxation areas and shore excursions.