As the nuclear power plant crisis affecting Japan unfolds, Cathay Pacific is seeking clarification of international guidelines in the event that radioactive material and toxic chemicals enter the airspace.
A person close to the airline said it was also working out how it would deal with radiation-affected passengers, including the possibility of removing potentially contaminated seats.
Cathay Pacific chief executive Tony Tyler said the airline would maintain services to Japan at their current level of eight flights a day.
The special one-way fare would remain at HK$5,755 until March 27, a spokesman said.
Most airlines had arranged for flight crews flying to Japan to stop overnight at nearby cities in light of the nuclear crisis.
Only Lufthansa and Alitalia believe the current situation warrants the suspension of flights to Tokyo's two airports.
The person close to Cathay said the company was monitoring the situation with the civil aviation authorities in Hong Kong and Japan, and would refer to international practices - including those issued by the Association of European Airlines and International Civil Aviation Organisation - if the suspension of services became necessary.
It is understood the airline has also considered contingency measures should a passenger be found, on landing at Hong Kong International Airport, to have been exposed to radioactive materials.
'Should the seat be removed, or just the seat covers? Whether a professional third party or government officials should do it? Those types of questions,'' the person said.
The London office of the Volcanic Ash Advisory Centre on Wednesday issued a warning on possible release of radioactive material covering airspace zones over Japan, Russia, China, the United States and South Korea.
However, aircraft engineer Johnny Chung said at 30,000 to 40,000 feet, radioactive substances would have dissipated and cause little harm.
Lufthansa said it diverted its flights to Tokyo, Osaka and Nagoya to ensure that its operations to Japan remained as stable as possible and provide sufficient capacity for passengers.
Three mainland carriers - Air China, China Eastern and China Southern - have scheduled more flights to Japan amid an overwhelming increase in the number of Chinese nationals rushing home.
China Eastern said it would have 50 flights daily between China and Japan from yesterday until Wednesday. It put on 60 flights yesterday. China Southern said it operated 26 flights between the mainland and Japan yesterday.
Dalian Zhoushuizi International Airport in Liaoning province also began taking precautions from Monday, monitoring the body temperatures and radiation levels of travellers from Japan and providing airport staff with better protection. A Shanghai airport staff member said an emergency meeting was held yesterday and a radiation checkpoint might be set up, pending instructions from the Civil Aviation Administration of China.