SINGAPORE - Singapore Airlines (SIA) has asked pilots and cabin crew on a Milan-Singapore flight to take leave of absence and monitor their health closely after a passenger later tested positive for the coronavirus.

The infected woman landed at Changi Airport, then left for Auckland on Feb 25 on an Air New Zealand (Air NZ) flight. She was subsequently confirmed to have the Covid-19 infection on Wednesday (March 4).

Flight NZ283, a codeshare service with SIA, was also carrying SIA passengers, The Straits Times found out.

Air NZ said the woman, who flew from Singapore to Auckland, then went to Palmerston North on flight NZ5103 on Monday and returned to Auckland on NZ8114 the same day.

An SIA spokesman said last night: "Singapore Airlines has been informed that a passenger who is confirmed to have Covid-19 travelled on our flight from Milan to Singapore on Feb 24. We are assisting the relevant authorities to identify the passengers and crew who were on board the flight."

Crew who were on the aircraft have been told to go on a leave of absence and to closely monitor their health, the spokesman added.

NZ media said the patient on the Air New Zealand flight, a local woman in her 30s, was in self-isolation at home with clinical support. She reportedly developed symptoms once back in NZ.

The airline said it was working with NZ authorities to identify and contact customers who travelled on the Singapore service and the two regional flights.

A spokesman for Singapore's Ministry of Health (MOH) said: "We are working closely with the NZ Ministry of Health and the respective airlines to conduct contact tracing for the crew and flight passengers who may have had contact with the confirmed case of Covid-19 while the case was infectious."

Details were not available on the number of people who have come into contact with the patient, who had transited at Changi Airport after returning from northern Italy, or whether any of these contacts were Singaporean or Singapore residents.

Air NZ chief medical officer Ben Johnston said: "Our aircraft already undergo a thorough cleaning process, which includes cleaning surfaces such as tray tables and in-flight entertainment screens with a disinfectant that kills viruses.

"We also remove all headsets, headrest covers, pillow covers, and blankets after every international flight. Domestic and regional services surfaces and bathrooms are wiped with disinfectant spray.

"The three aircraft this customer flew on will now also undergo a deep clean."

Singapore has reported 112 cases with no deaths. NZ has two confirmed cases, including the Air NZ one.