An Australian member of the WHO-led team visiting the Chinese city of Wuhan says he has been surprised by the complexity of getting to the origins of the COVID-19 pandemic and that years of research lies ahead.

Professor Dominic Dwyer, a microbiologist and infectious diseases expert, says the team in Wuhan has received the access it requested from Chinese authorities as it tries to understand the early days of the coronavirus outbreak first detected in Wuhan.

“Everybody knows how it really exploded out of Huanan market in Wuhan but the key is what was happening around that time and before,” Professor Dwyer said.

Officials in Beijing have pushed the idea that the virus could have originated elsewhere.