Beijing insisted on Tuesday that it had shared information on Covid-19 "without holding anything back", after the World Health Organization implored China to offer more data and access to understand the disease's origins.

Covid-19, which first emerged in the central Chinese city of Wuhan, killed millions of people, shredded economies and crippled health systems.

The WHO published a statement on Monday saying it was a "moral and scientific imperative" for China to share more information.

"Five years ago... China immediately shared epidemic information and viral gene sequence with the WHO and the international community," foreign ministry spokeswoman Mao Ning said on Tuesday.

"Without holding anything back, we shared our prevention, control and treatment experience, making a huge contribution to the international community's pandemic-fighting work," she told reporters at a regular press briefing.

This month marks the fifth anniversary since the outbreak in Wuhan was first reported.

Over the course of the Covid-19 pandemic, the WHO repeatedly criticised Chinese authorities for their lack of transparency and cooperation.

A team of specialists led by the WHO and accompanied by Chinese colleagues conducted an investigation into the pandemic's origins in early 2021.

In a joint report, they favoured the hypothesis that the virus had been transmitted by an intermediary animal from a bat to a human, possibly at a market.

Investigators have not been able to return to China since, and WHO officials have repeatedly asked for additional data.

AFP

File photo by Reuters.

China says shared Covid information 'without holding anything back'