China has played down concerns from the World Health Organization (WHO) about a delay in authorisation for a visit by a team of experts looking into the origins of COVID-19, saying arrangements were being worked out.

The head of the WHO, Tedros Adhanom Ghebreyesus, said on Tuesday he was “very disappointed” that China had not authorised the entry of the team for the investigation, which he said was a WHO priority.

He told a news conference in Geneva that China had “not yet finalised the necessary permissions” for the WHO team’s arrival, adding he was “very disappointed with this news”.

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

The coronavirus was first reported in the Chinese city of Wuhan in late 2019 and has since spread around the world.

Much remains unknown about its origins and China has been sensitive about any suggestion it could have done more in the early stages of the pandemic to stop it.

Foreign ministry spokeswoman Hua Chunying, told a news briefing in Beijing that the problem was “not just about visas” for the WHO team.

Asked about reports that the dates had been agreed upon, she said there had been a “misunderstanding” and the two sides were still in discussions over the timing and other arrangements and “remain in close communication”.

“There’s no need to overinterpret this,” she said.

China’s experts were also busy dealing with a renewed spurt of coronavirus infections, with many locations entering a “wartime footing” to stop the virus, she said.

The 10-strong team of international experts had been due to set off in early January as part of a long-awaited mission to investigate early cases of the disease.

China has been seeking to shape the narrative about when and where the pandemic began, with senior diplomat Wang Yi saying “more and more studies” showed that it emerged in multiple regions.

WHO emergencies chief Mike Ryan has previously called this “highly speculative”.

The mission is due to be led by Peter Ben Embarek, the WHO’s top expert on animal diseases that cross the species barrier, who went to China on a preliminary mission last July.