Japan's Foreign Ministry plans to launch a research and study project to help create international rules on how to handle infectious disease outbreaks onboard cruise ships.

In February, coronavirus cluster infections were confirmed aboard the Diamond Princess, a cruise vessel registered in Britain and operated by a US company.

Major airlines in Japan say they will consider suspending or cutting more international flights as the foreign ministry raised its travel alert for the entire world on Wednesday, urging Japanese people to refrain from non-essential overseas trips.

Japanese airlines have already suspended or reduced flights on a wide range of international routes, including China, South Korea, Europe and the United States, amid the coronavirus outbreak.