Furious customers have vowed never to fly with Qantas again after boss Alan Joyce said that vaccinations against COVID-19 would be mandatory for all passengers on international flights.

He made global headlines after he revealed that once a vaccine became available, it would be a condition of travel with Qantas.

“For international travellers, we will ask people to have a vaccination before they get on the aircraft,’’ he said on A Current Affair last night.

“Certainly, for international visitors coming out and people leaving the country, we think that’s a necessity.”

#BREAKING: QANTAS CEO confirms that proof that you've been vaccinated for COVID-19 will be compulsory for international air travel onboard his aircraft. #9ACA pic.twitter.com/dhk3Hsnxn9

— A Current Affair (@ACurrentAffair9) November 23, 2020

Joyce also suggested that if people weren't happy with that rule, they might struggle to find an alternative airline to fly with.

“I think that’s going to be a common thing, talking to my colleagues in other airlines around the globe,” he said.

People immediately rejected the policy, with comments on Twitter flying.

“What right does Alan Joyce have to demand that we will only be allowed to travel with Qantas if we first prove we have been vaccinated against COVID-19?” someone asked on Twitter.

“My health and vaccination status is none of his concern.”

"I will never use Qantas ever again and I hope the world boycotts any company that uses this behaviour," another wrote.

“I’m no anti-vaxxer, but forced vaccination, especially of such a new drug, is NOT okay,” one person tweeted.

“If Qantas really go ahead, we may have to seek judges’ ruling.”

The Federal Government has said that a COVID-19 vaccine would not be mandatory in Australia, but could become a condition of entry or re-entry into the country.

“While the Australian Government strongly supports immunisation and will run a strong campaign to encourage vaccination, it is not mandatory and individuals may choose not to vaccinate,” the Australian COVID-19 Vaccination Policy says.

“There may however, be circumstances where the Australian Government and other governments may introduce border entry or re-entry requirements that are conditional on proof of vaccination.”

The International Air Transport Association has also said it is in the final stages of developing a digital health pass that would co-ordinate information about COVID testing and vaccinations to support the reopening of international borders.

The IATA Travel Pass would “manage and verify the secure flow of necessary testing or vaccine information among governments, airlines, laboratories and travellers”, the industry body said.

“Testing is the first key to enable international travel without quarantine measures. The second key is the global information infrastructure needed to securely manage, share and verify test data matched with traveller identities in compliance with border control requirements,” the IATA’s director general and chief executive Alexandre de Juniac said.

IATA’s senior vice president of airport, passenger, cargo and security, Nick Careen, said the main priority was to “get people travelling again safely”.

“In the immediate term that means giving governments confidence that systematic COVID-19 testing can work as a replacement for quarantine requirements. And that will eventually develop into a vaccine program,” he said.

“The IATA Travel Pass is a solution for both.”