Tedros Adhanom Ghebreyesus's comments mark a rare critique of Beijing by the head of the World Health Organization.
China has failed to grant permission for international inspectors to visit Wuhan as part of a study into the origins of the deadly coronavirus, according to World Health Organization (WHO) chief Tedros Adhanom Ghebreyesus.
Speaking on Tuesday, Dr Tedros said that a number of the team of scientists were already on their way to the Chinese city where COVID-19 first emerged when it emerged they did not have the necessary clearances from Beijing.
He said that China had previously agreed to allow the international scientific team to enter the city and carry out its work.
"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," he told a news conference in Geneva.
"And I have once again made it clear that the mission is a priority for WHO and the international team. I have been 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."
His comments marked a rare critique of Beijing by the WHO head, who had previously praised the authorities in China for their response to the virus.
COVID-19, which has killed more than 1.8 million people worldwide, first emerged at a live animal market in the central Chinese city of Wuhan in December 2019.