GENEVA (AFP) - The World Health Organisation said Monday that a key emergency committee would meet this week to discuss a new Sars-like virus spreading across China after it reached three other Asian countries.

The WHO panel will meet in Geneva on Wednesday (Jan 22) to determine whether to declare the outbreak "a public health emergency of international concern" - a rare designation only used for the gravest epidemics.

The decision came as a Chinese government expert said Monday that the virus, which has so far killed three people, was contagious between humans, fuelling fears of a major outbreak as millions travel for the Lunar New Year holiday.

The World Health Organisation has meanwhile said an animal source seemed to be "the most likely primary source" with "some limited human-to-human transmission occurring between close contacts".

The new coronavirus strain, first discovered in the central city of Wuhan, has caused alarm because of its connection to Severe Acute Respiratory Syndrome (Sars), which killed nearly 650 people across mainland China and Hong Kong in 2002-2003.

The total number of people diagnosed with the new virus rose to 218, as Beijing and Shanghai confirmed their first cases on Monday while more than a dozen more emerged in southern Guangdong province.

Over the weekend, 136 new cases were found in Wuhan, according to state broadcaster CCTV.

South Korea on Monday also reported its first case - a 35-year-old woman who flew in from Wuhan. Thailand and Japan have previously confirmed a total of three cases - all of whom had visited the Chinese city.

WHO said its emergency committee convened by agency chief Tedros Adhanom Ghebreyesus on Wednesday would determine whether the new coronavirus strain represents "a public health emergency of international concern".

In WHO parlance, that means an "extraordinary event" in which an outbreak constitutes "a public health risk to other States through the international spread of disease" and requires a vigorous international response.

The agency has only used the label a handful of times previously, including during the H1N1, or swine flu, pandemic of 2009, for the Ebola epidemic that devastated parts of West Africa from 2014 to 2016, the surge of the Zika virus in 2016 and the Ebola outbreak raging in eastern Democratic Republic of Congo since 2018.