Hundreds of passengers who tested negative for the new coronavirus have begun leaving a quarantined cruise ship in Japan amid heavy criticism over the country's handling of the outbreak, the BBC reports.

One Japanese health expert who visited the Diamond Princess at the port in Yokohama said the situation on board was "completely chaotic".

US officials said moves to contain the virus "may not have been sufficient".

Passengers have described the difficult quarantine situation on the vessel.

At least 542 passengers and crew on the Diamond Princess have so far been infected by the Covid-19 virus - the biggest cluster outside mainland China.

The ship was carrying 3,700 people in total.

Several nations are evacuating their citizens from the ship as infections continue to rise.

The cruise ship was put in quarantine in Yokohama in early February after a man who disembarked in Hong Kong was found to have the virus.

Passengers were initially isolated in their cabins and later allowed to sporadically go out on deck.

Despite the quarantine measures, day by day the number of infected people grew rapidly.

Covid-19 has now claimed 2,004 lives in China, according to the latest Chinese data released on Wednesday, February 19.

There have been 74,185 confirmed infections recorded in mainland China and about 700 cases in other countries.