Another two people have tested positive in Hong Kong for the deadly Wuhan virus, taking the total in the SAR so far to four.

Officials said on Friday that the latest patients are both women in their 60s, with one being treated in Tuen Mun Hospital and the other in Sha Tin's Prince of Wales Hospital.

The controller of the Centre for Health Protection, Wong Ka-hing, said both women had recently been in the Hubei city of Wuhan, which is the epicentre of the spreading outbreak.

Further tests were being carried out to double check that the women have the illness that has infected hundreds on the mainland and killed more than two dozen.

Meanwhile, the health authorities also revealed that a second patient confirmed to have the illness in Japan had changed planes at Hong Kong International Airport.

Japanese officials had said earlier in the day that this patient is a man in his 40s who is a resident of Wuhan. He was said to have been suffering from fever for several days before he arrived in Japan.

The man flew to Hong Kong from Wuhan on Cathay Dragon flight KA855 on January 19 and then travelled to Tokyo's Narita Airport on Cathay Pacific flight CX500, also on January 19, officials said.

They added that they are trying to trace the passengers who sat near the man on the two flights.