A team of World Health Organisation (WHO) experts planning to investigate the origin of Covid-19 have been denied entry into China by officials.

The head of the WHO says he is “disappointed” Chinese officials have not finalised the permissions to allow a team of experts into the country.

In a rare critique of Beijing, WHO director general Tedros Adhanom Ghebreyesus said members of the international scientific team began to leave their home countries in the last 24 hours as part of an arrangement between the WHO and the Chinese government.

“Today, we learned that Chinese officials have not yet finalised the necessary permissions for the team’s arrival in China,” he said during a news conference in Geneva.

“I’m very disappointed with this news, given that two members had already begun their journeys and others were not able to travel at the last minute, but had been in contact with senior Chinese officials.” 

Tedros said he “made it clear” that the mission was a priority for the UN health agency, and that he was “assured that China is speeding up the internal procedures for the earliest possible deployment.”

“We are eager to get the mission underway as soon as possible,” he said.

The experts drawn from around the world are expected to visit the city of Wuhan, the original epicentre of the virus and where the pandemic is thought to have originated at the end of 2019. 

Dr Michael Ryan, the WHO’s emergencies chief, said the deployment had been expected to start on Tuesday but the crucial approvals, such as visa clearances, had not yet been granted.

The Chinese government has been strictly controlling all domestic research into the origins of the virus, an AP investigation found, and state-owned media have played up reports that suggest the virus could have originated elsewhere.

Chinese foreign minister Wang Yi said recently that “more and more research suggests that the pandemic was likely to have been caused by separate outbreaks in multiple places in the world.”

Ryan said Tedros had “taken immediate action” by speaking with unspecified senior Chinese officials, and had “fully impressed upon them the absolute critical nature of this.”

“We hope that this is just a logistical and bureaucratic issue that can be resolved very quickly,” Ryan added.

The WHO chief previously met with Chinese President Xi Jinping as the pandemic was emerging at the start of 2020.