The experts will work with Chinese scientists to determine the source of the pandemic, as they still store the strains for analysis and study purposes, Ihor Perehinets, a technical adviser at the WHO's European office, said at a media briefing.
Two members of the World Health Organization mission were barred by Chinese officials from boarding a flight to Wuhan after testing positive for antibodies during a final layover in Singapore, where they remain to be retested.
But two members had tested positive for so-called IgM antibodies, which are usually the first antibodies produced by the immune system when a virus attacks.
After landing, the team will spend two weeks in quarantine before visiting various sites to investigate how the coronavirus first jumped to people, said Ben Embarek, an expert in zoonosis, diseases that can be transmitted from animals to humans.
According to WHO's published agenda for the research team, there are no plans to assess whether there might have been an accidental release of the coronavirus at the lab, as some American politicians, including President Donald Trump, have claimed.
The group left the airport terminal in Wuhan through a plastic quarantine tunnel marked "epidemic prevention passage" for global arrivals and boarded a cordoned-off bus that was guarded by half a dozen security staff in full protective gear.
A group of 10 scientists is set to interview people from research institutes, hospitals and the seafood market linked to the initial outbreak.
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Team members did not speak to reporters, although some waved and took pictures of the media from the bus as it departed.
In another daily spike in new COVID cases in China, the Commission announced 138 newly confirmed COVID-19 cases on Wednesday in the Chinese mainland, of whom 124 were locally transmitted.
The latest death raises the toll to 4,635 among 87,844 cases in the country.
But it is unclear whether China will fully comply with the team's requests.
Originally, the experts planned to visit China earlier this month, but their arrival was delayed due to Beijing not finalizing permissions to allow the group into the nation, leading to WHO Director General Tedros Ghebreyesus to remark that he was "very disappointed" with the situation.
"We are looking for the answers here that may save us in future - not culprits and not people to blame", the WHO's top emergency expert, Mike Ryan, told reporters this week, adding that the World Health Organization was willing to go "anywhere and everywhere" to find out how the virus emerged.
China, which celebrated victory over the virus a year ago with businesses and schools reopening and awards handed out to virus experts and front-line medical workers, is now battling resurgent cases. But they later said they could not rule out the possibility that the virus had come from overseas because it has been detected in imported food.
He said they would look closely into the first human cases of the virus, as well as activity around traditional Chinese markets in the city.