The virus, which originated in China late last year, has claimed over 1,100 lives and spread to other countries. Japan, which shares the rank of the world's top energy importers with China, has the second largest number of cases.

World Health Organization (WHO) has warned the epidemic poses a global threat akin to terrorism.

IP Week, the oil industry's main annual gathering, is also known for its lavish evening parties where companies and traders cement business deals struck during the day.

South Korean refiners GS Caltex and SK Innovation, owner of SK Energy refiner, told Reuters they week not going to attend IP Week this year amid virus outbreak.

"GS Caltex is not attending the IP week in the aftermath of China's virus outbreak," its spokesman said. SK Innovation official said his company will rely on its London-based staff as the Singapore office had decided to skip the event this time.

China's staff of Petrochina, Tokyo offices of Japan's Mitsubishi, Mitsui and Inpex along with Singapore offices of European majors, Eni and Total, were recommended to miss IP Week this year, sources familiar with the plans told Reuters.

"We had several meetings in London with Asian counterparties cancelled," a trader working in the Asian market and based in Europe said. He added his bosses were also considering skipping the event this year.

Several Chinese independent or "teapot" refiners also cancelled its trips to London IP Week this year, two traders working with the companies said.

JPMorgan's China team was also asked not to attend IP Week events, a source told Reuters. According to two other sources in Asian companies, the main concern is that travellers from Asia may be quarantined on arrival, ruining their business plans.

"As a result of travel bans imposed by a number of governments in Asia, some speakers and delegates will understandably not be attending, including all from mainland China," a spokesman of Energy Institute, the host of the main IP Week conference, said in a reply to Reuters enquiry.

"IP Week is going ahead as planned and delegates are being advised in line with the latest advice of the British government," he added.

A Mitsubishi official said that its oil staff will attend the IP Week as planned.

A Mitsui spokesman said most of its London-based staff would take part in the event, declining further comment. An Inpex spokesman said staff planned to attend, but it was "treating the COVID-19 outbreak with concern ... closely monitoring the situation."

"Several people from Total will attend the IP Week, including some coming from our Singapore offices," a press representative of Total told Reuters.

Eni declined to comment. Petrochina and JPMorgan did not reply to requests for comment.

(Reporting by Olga Yagova in MOSCOW, Jane Chung in SEOUL, Ron Bousso in LONDON, Aaron Sheldrick in TOKYO, Additional reporting by Bate Felix in PARIS; Writing by Olga Yagova; Editing by Katya Golubkova and David Evans)

By Olga Yagova, Jane Chung and Ron Bousso