The shape of post-pandemic travel could be quite different, with the likelihood a digital Covid-19 vaccine passport will be required before travellers even set foot on an international flight.

Last week the International Air Transport Association or IATA began a two-week trial of its digital Travel Pass on flights between Singapore and London.

With a trans-Tasman bubble expected to be in place by the end of April, Air New Zealand has already confirmed it will trial the IATA Travel Pass on its Auckland to Sydney route next month.

Auckland University of Technology computer science professor Dave Parry said the information will be contained on your smartphone in an "electronic wallet" which links identification with vaccination information.

"When you get your vaccination it'll be loaded up into some sort of national system for vaccine recording and then you'll get a record of it yourself, you'll put this in your phone, it will link to your ID and then when you go to the airport the system will read this data and confirm that you are who you say you are because you've got your passport as well."

He said the airline will then check that the information is valid before allowing you to board the plane.

That would include checking that the vaccinator and the vaccine are valid and flagging any potential problems which may require further information or prevent the person from flying, he said.

"Effectively what it's doing is confirming for the airline that your vaccine has been done and that you're the person who got it and also that they can check against the list of valid people who offer the vaccine to show that that's acceptable for the destination you're headed for."

The Ministry of Health looking to set up a separate vaccine database specifically for Covid-19 which is separate from the existing vaccine database.

Parry said the system will rely on New Zealand having a reliable vaccine register available.

A potential drawback is that other countries are likely to have their own system for vaccine passports so you may end up needing multiple vaccine passports, he said.

Parry said both Apple and Android have ways of storing information securely on smartphones.

But he said it will not work for everyone, including those without those phones, or without the latest phones or where the operating system is not up-to-date.

"It's going to be quite difficult to ensure that everybody has got this effectively for very fast movement, I think the first few people will put a lot of effort in and then of course you get into families, groups travelling together, do we know that everybody's done this or not in our group?"

He said the back-up will be the QR code which can be generated from the file and it's likely that will be able to be generated through a normal computer system.

Parry said it's reasonably secure in terms of fraud because it is only linking your identification to your vaccine record.

"The vaccine record gives a link to the vaccine provider and so if there's any suspicion about whether you were given that vaccine then the airport can contact the vaccine provider."

How standardised would an IATA travel pass be?

IATA already runs systems where it checks people's visa status so it has gained a level of trust associated with that, Parry said.

"So airlines get fined if they put someone on a plane who can't go into the country of destination, so airlines are very keen to understand what visas and what access you've got."

Parry believes that the IATA Covid passport will become a baseline standard that most international flights will accept.

"You might get internal flights in different countries that don't where you have to have the local version as well, but I think for most international travel this will be the version that's used."

Parry said the airlines and IATA are aware of a potential problem with people being excluded from other areas such as schools or cafes on the basis of their vaccine information.

He said IATA and the airlines would be reluctant if Covid passports were used for anything other than travel.

"So you won't be getting a version of the IATA software for cafes or whatever, it will just be for the airlines."