Hong Kong has boosted preventive measures against a pneumonia outbreak first reported in the central mainland city of Wuhan last month by making it compulsory for all air passengers arriving from the Hubei provincial capital to fill in a health declaration form.

Travelers arriving in the special administrative region by train are not required to do so as body temperature checks are being carried out at the West Kowloon high-speed rail terminus, where two trains arrive each day from Wuhan.

The measures are being enforced as the total number of confirmed cases of the new coronavirus shot up to more than 200 in various mainland cities and in Thailand, Japan and South Korea.

Director of Health Constance Chan Hon-yee said on Monday travelers who violate the declaration requirement, or knowingly provide false information, face a maximum jail term of six months and a fine of HK$5,000 ($644) under the Prevention and Control of Disease Regulation.

Currently, there're about 15 direct weekly flights from Wuhan to Hong Kong.

The Centre for Health Protection has lowered the mandatory reporting threshold for suspected patients to those who have been identified with fever and acute respiratory illness, or pneumonia, and have been to any city in Hubei or any mainland hospital in the past 14 days.

As of 8 pm on Monday, there had been 218 confirmed cases of the mysterious pneumonia across the mainland, including 198 cases in Wuhan alone, 14 cases in Guangdong province and five cases in Beijing, including three people who have died.

Across Asia, Thailand has reported two confirmed cases, with Japan and South Korea one case each.

With an expected peak in travel ahead of the Lunar New Year holiday that starts on Friday, Chan said body temperature check facilities have been in place at all Hong Kong entry ports as a major part of the government's preventive measures against the mystery virus.

In the 24 hours before Monday noon, seven more suspected cases were reported in the SAR, bringing the total number to 106 since Dec 31, but none has been infected with the new coronavirus.

Health officials warned that Hong Kong might see its first confirmed case any time, and urged residents to stay vigilant and pay attention to personal hygiene, especially when visiting the affected areas.

The World Health Organization warned on Monday the SARS-family virus, believed to have come from a wholesale seafood market in Wuhan that also sells game meat, could spread through limited human-to-human transmission during close contact.

The incubation period of the disease is about two weeks, based on known information, according to health authorities.