Wild animals are likely to be the origin of the new coronavirus that has caused a pneumonia outbreak in Wuhan, Hubei province, top public health experts said.

Gao Fu, head of the Chinese Center for Disease and Control, said on Monday that evidence linking wild life and the coronavirus has been found in a seafood market in Wuhan, where the outbreak was first reported last month.

"However, the source of infection is still not clear, and we have not identified the animal," he said.

All the six coronavirus known to humans, including the one that caused severe acute respiratory disease, originated from wild mammals, Gao said.

Zhong Nanshan, a member of the Chinese Academy of Engineering, and a prominent expert in respiratory diseases, also said on Monday the new virus is likely to have originated from wild mammals.

Following the outbreak of the disease, local authorities in Wuhan closed the seafood market, where a number of wild animals were kept, to prevent spread of the virus, he said.

Gao said the new virus has kept evolving since it was identified earlier this month as it adapts to human environment, with the latest discovery that it can transmit between humans, and experts are racing against time to get a better knowledge of the virus for its prevention and control.

A total of 224 cases of the new virus were reported on the Chinese mainland as of Monday night, including 198 in Wuhan.

Fifteen medical workers in Wuhan have been confirmed with the disease, and another suspected case involving a medical worker had been identified, the city's healthy authority said early morning on Tuesday. One case is in critical condition, and all the cases are under quarantine.