An advance team of international experts led by the World Health Organization (WHO) has left for Beijing to help investigate China's coronavirus epidemic, the Geneva-based agency said on Sunday.

WHO Director-General Tedros Adhanom Ghebreyesus, who made a trip to Beijing for talks with President Xi Jinping and Chinese ministers in late January, returned with an agreement on sending an international mission.

But it has taken nearly two weeks to get the government's green light on its composition, which was not announced, other than to say that WHO veteran Dr. Bruce Aylward, a Canadian epidemiologist and emergencies expert, was heading it.