The World Health Organisation's (WHO) top emergency expert said on Friday the search for the origin of the coronavirus was being "poisoned by politics", days after US President Joe Biden ordered aides to find answers.

Since the virus outbreak that emerged in the central Chinese city of Wuhan in December 2019, scientists have been trying to solve the puzzle of where the virus originated.

"We would like for everyone out there to separate, if they can, the politics of this issue from the science. This whole process is being poisoned by politics," Mike Ryan told reporters.

A WHO-led team spent four weeks in and around Wuhan with Chinese researchers and said in a report in March that...