A team of WHO experts will land directly in Wuhan on Thursday, China's foreign ministry said Tuesday, starting their long-delayed probe into Covid-19 at the virus epicentre.

The ten scientists will investigate the origins of the new virus in a politically fraught mission that comes more than a year after the pandemic began and after accusations Beijing has tried to thwart the project.

The World Health Organization team will leave from Singapore and fly straight to Wuhan, the central city where the first cluster of cases was detected in December 2019.

Foreign ministry spokesman Zhao Lijian told reporters this was the "current plan" and said the WHO team was set to arrive Thursday.

It is expected that they will have to complete two weeks of quarantine due to China's strict border restrictions.

The investigation had been set to start last week but a last-minute hold up over entry permissions in China scuppered plans.

The WHO insisted this week that the investigation was not looking for "somebody to blame".

WHO emergencies director Michael Ryan said the delayed mission was about science, not politics.

"Understanding the origins of disease is not about finding somebody to blame," Ryan told a press conference in Geneva.

"It is about finding the scientific answers about the very important interface between the animal kingdom and the human kingdom."

Experts say solving the mystery of how the virus first jumped from animals to humans is crucial to preventing another pandemic.

The novel coronavirus has killed nearly two million people since the outbreak first emerged in Wuhan.

Thousands of mutations in the virus have taken place as it has passed from person to person around the world, but new variants recently detected in Britain and South Africa are seemingly more contagious.

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