Updated 9.18pm - Italy's health ministry said Thursday two Chinese cruise ship passengers had tested negative for the coronavirus, meaning thousands of stranded passengers could disembark.

Costa Cruises was offering to pay for food and hotels for some 1,140 people who had been due to disembark at the Civitavecchia port near Rome early Thursday, and the Costa Smeralda was to set sail again Friday, Italian media said. 

The Lazzaro Spallanzani national institute for infectious diseases examined samples taken from a Chinese woman who fell ill with a fever as well as her travelling companion.  

It came as China reported its biggest single-day jump in coronavirus deaths and global fears deepened over a spread of the disease, with at least 15 countries confirming infections.

Cruise line Costa Crociere confirmed the ship, which is currently in the port of Civitavecchia, had been on lockdown with some 7,000 people in total including the crew on board.

Costa said a 54-year old woman from Macau "was placed in solitary confinement in the on-board hospital last night with her travel companion", and the crew was following instructions from the health ministry.

Some 750 other Chinese passengers are on board and all appear to be in good health, media reports said.

The Smeralda, the company's flagship and the fifth-largest cruiser in the world, had sailed in from Palma de Mallorca as part of a one-week trip in the western Mediterranean.

Italy's Prime Minister Giuseppe Conte earlier said the government was "not worried, but vigilant and cautious".

Adriano Pavan, whose son and two grandchildren were on board and who had travelled to the port to meet them off the ship, told AFPTV that he was "quite worried".

"My son told me the Chinese couple had been wearing masks for the past two or three days, but they thought nothing of it".