TAIPEI (AFP) - A Taiwanese couple who recently tested positive for the new coronavirus, which originated in the Chinese city of Wuhan, likely picked up their infections on a flight from Hong Kong to Italy, the authorities said.

The couple, both retirees in their 50s, had no history of travel to the Chinese mainland but were admitted to hospital on Feb 4, three days after returning from a holiday in Italy.

They transited in Hong Kong on their journey to and from Europe.

"After consultations with experts, we came to the conclusion that the most likely place of infection was on board the aircraft from Hong Kong to Europe, where it was a confined space," Health and Welfare Minister Chen Shih-chung told reporters late Thursday.

The case highlights how air travel can spread the virus, which has killed more than 600 people in China, where the outbreak first began.

Hong Kong has 24 confirmed infections, including one death, and transmissions among locals who have not travelled to China recently are increasing.

Taiwan confirmed five new cases on Thursday - including the couple - bringing their total number to 16.

Also among the new infections was a woman in her 40s who spent the Chinese New Year in Macau with three other family members.

Taiwan has stopped all Chinese nationals from entering its borders and has temporarily suspended all online visa applications for Hong Kong and Macau residents.

Other foreign nationals who have visited China, Hong Kong and Macau in the past 14 days are also barred from entry.

"I want to advise everyone to wear a face mask at all times when travelling in an aircraft and also in confined spaces such as inside airports," Mr Chen said.