The World Health Organization said Monday it had received reassurances from Beijing that international experts would soon be able to travel to China to help investigate the animal origins of Covid-19.

"We fully expect and have reassurances from our Chinese government colleagues that the trip to the field... will be facilitated, and as soon as possible," WHO emergencies director Michael Ryan told a virtual press briefing.

"We need to be able to have the international team join our Chinese colleagues... and look at the results and the outcomes of (their) studies and verify the data on the ground," he said.

Ryan hailed the "tremendous amount of scientific investigation" done by the Chinese, but said international experts needed to go in "in order that the international community can be reassured about the quality of the science."

"This is extremely important, and we are continuing to expect that that be the case."

The WHO has for months been working to send a team of international experts, including epidemiologists and animal health specialists, to China to help probe the animal origin of the novel coronavirus pandemic and how the virus first crossed over to humans.

The UN health agency sent an advance team to Beijing in July to lay the groundwork for the international probe, but it has remained unclear when the larger team of scientists would be able to travel to China to begin epidemiological studies to try to identify the first human cases and their source of infection.

Scientists initially believed the killer virus jumped from animals to humans at a market selling exotic animals for meat in the city of Wuhan, where the virus was first detected late last year.

But experts now think the market may not have been the origin of the outbreak, but rather a place where it was amplified.

It is widely assumed that the virus originally came from bats, but the intermediate animal host that transmitted it between bats and humans remains unknown.

Late last month, the WHO said the team of 10 international experts it has set up had held their first meeting with their Chinese counterparts, albeit virtually.

Ryan said Monday that the teams had continued to hold regular virtual meetings as they prepared for the mission.

"Clearly we all need to understand the origin of the virus, we all need to understand where it has come from, not least to understand where it may re-emerge in the future," he said.

"I believe our Chinese colleagues are just as anxious to find those answers as we are."