The All Nippon Airways (ANA), Japan's largest airline, on Monday began testing a mobile app to certify the Covid-19 status of passengers, in a move towards the country's potential issuance of "vaccine passports" aimed at making international travel smoother and safer.

The trial of the International Air Transport Association Travel Pass (IATA Travel Pass) will be conducted on the carrier's international flights connecting Tokyo with Honolulu and New York through June 6, Xinhua news agency quoted ANA as saying.

"As it is important to create an environment in which passengers can travel with peace of mind, the aviation industry has high hopes for the IATA app," ANA executive Tadashi Matsushita, who is heading the project, said.

The smartphone app, developed by a global industry body, works by displaying passengers' polymerase chain reaction (PCR) test results and vaccination status.

"IATA Travel Pass enables passengers to easily verify whether they meet the Covid-19 testing requirements of their destination and share their test results with airlines and authorities in a secure way," ANA President Yuji Hirako was quoted as saying previously.

Passengers involved in the trial at Tokyo's Haneda airport on Monday said the process was smooth as they only had to show their phones and no other documents.

ANA has said that 32 airlines have committed to joining the trial, with the app similar to one previously tested called CommonPass, which has been developed with the involvement of the World Economic Forum.

CommonPass allows passengers to prove their Covid status by having a QR code on their smartphones scanned prior to boarding a flight, and, ostensibly, in the near-future, making overseas travel digitalised and standardised for those who have been vaccinated against the virus.