Hong Kong on Wednesday recorded nine more confirmed cases of novel coronavirus infections, increasing the city's tally to 129. Most cases are related to overseas travel, while another patient had an incubation period of over 20 days.

Six newly confirmed cases were from a tour group to Egypt, with all nine members of the group infected by the virus.

Hong Kong's health authorities noted the seriousness of the group infection — warning of a possible community outbreak in Egypt.

The Egypt tour began on Feb 27, and returned in Hong Kong on Flight TK70 on Saturday. The tour included four couples and a tour guide. Three members of the group were already confirmed to be infected on Tuesday.

The 23-year-old tour guide, with a good health record, lives in Telford Gardens in eastern Kowloon. He developed a fever on Tuesday on his way to the quarantine center as a close contact.

Another infected tour member is a 57-year-old male worker with the Food and Environmental Hygiene Department, who lives in Block 7, Bellagio, in the New Territories.

The worker, who has an underlying disease, coughed and developed a fever on Sunday, but returned to work on Monday at the Cheung Chau Municipal Services Building.

His 52-year-old wife, who was also on the Egypt tour, started coughing on Sunday, and was confirmed to be infected on Wednesday.

A 59-year-old female tour member was confirmed to be infected on Wednesday.

Another couple from the group, both 63 years of age and retired, was also confirmed to have it. They live in Block 26, Laguna City in eastern Kowloon.

Another new case involves a 22-year-old female attendant on Cathay Pacific Flight CX320 from Spain and arrived in Hong Kong on Sunday. She worked in economy class.

The flight attendant, who didn't have a history of illness, visited Madrid and Amsterdam before returning to Hong Kong. She had a runny nose on Friday and developed a fever on Tuesday.

Earlier, a 19-year-old female student returned from a university in Spain on the same flight that was confirmed to be infected on Monday in the city of Dongguan, Guangdong province.

The head of the communicable disease branch of the Centre for Health Protection, Chuang Shuk-kwan, told a press briefing that special precautions regarding personal hygiene are needed for flight attendants. Anyone who has symptoms, even minor ones, should avoid going to work.

One of the two other cases is a 36-year-old woman with a good health record, the daughter of a 69-year-old patient hospitalized on Feb 16.

She stayed at the quarantine center for 14 days as a related contact without any symptoms and left on March 1. However, on Sunday, she had diarrhea and was confirmed to be infected on Wednesday.

Regarding the over-20-day incubation period, Chuang said the patient was likely to have been infected by her father.

She noted that the case is rather special, as the latest research showed that the incubation period of 99 percent of the cases around the world is less than 14 days.

Another new case is a 31-year-old woman, who was on Flight CX250 from London to Hong Kong on Feb 29. She had a fever on March 3. Two other people on the flight were confirmed to be infected last week.

The city has two more coronavirus patients discharged from the hospital. The total number of people who have recovered is now 66.