People in Ireland could be forced to use two different contact tracing apps to safely travel over the border.
They may be asked to download both the UK's NHS contact-tracing app and another being developed in the Republic to help identify close contacts of a confirmed case of Covid-19, it was reported on Sunday.
The Republic's Health Minister Simon Harris has previously signalled an all-island approach to tackling coronavirus.
But experts have warned that it will be "impossible" to make the UK's contact-tracing app work with the Republic's counterpart, creating a problem for people who travel across the border.
The NHS contact-tracing app, which is being trialled on the Isle of Wight after being developed by the health service's research arm NHSX, is expected to be used in Britain and here.
But Dublin has opted to work with Google and Apple to develop its contact-tracing app.
The Republic is aiming to release the app by the end of this month.
It will only be available on smartphones and by using Bluetooth technology.
The Sunday Telegraph indicated people here could be asked to use both the UK and Republic's apps.
A Stormont spokesperson told the newspaper that urgent talks are under way with officials in the Republic on how to facilitate people crossing the border for work or travel.
They said options under consideration "may include individuals in border regions or working across the island needing to download both versions of the apps".
Contact-tracing apps that are under development to track coronavirus rely on Bluetooth signals between phones. Two smartphone users with the app perform a digital "handshake" if they meet, recording anonymous keys from each phone.
If one user later comes down with coronavirus, the person they met is notified.
The NHS app uses a so-called centralised system, where data from the meetings is transferred to a database.
The system being used in the Republic is "decentralised" and data is only stored on the phones themselves.
This is seen as being more private by some experts.
Michael Veale, a lecturer at University College London working on contact-tracing technology, said "the systems work on different foundations".
The UK's app will rely on self-reporting, while other apps will rely on official tests for coronavirus.
Because the systems cannot communicate, it could leave people travelling across the border vulnerable.
On Sunday, Dr Veale said: "There are real signs that they might, particularly because the UK is a clear outlier internationally in using this particular type of approach, and that means it won't work well across borders.
"The Republic of Ireland said they're using a decentralised approach, and that will potentially create problems there if the administration chooses to effectively put in this kind of app."
Mr Harris said he hoped the Republic's contact tracing app would be made available on Apple iTunes so people here could use it. He said: "It is my intention that it would of course be available to residents through the UK Apple Store. I will come back about the ways in which we can make that happen and we are having conversations with colleagues in relation to an all-island approach, of which this is one element."
1. The app will be downloaded onto smartphones and use Bluetooth technology to work out when other app users are in close enough proximity to potentially spread the virus.
2. The data is recorded under an anonymous ID, rather than by the person's name. If someone starts showing symptoms, or tests positive for Covid-19, they are able to record that on the app.
3. The app then sends a notification warning of possible infection to all those phone users who have been in recent close contact with that person.
4. The app will be able to identify who might have been infected with the virus unwittingly, and help them to limit the spread by advising them to self-isolate.
5. The developers say widespread take-up of the app will be crucial in making sure it works effectively. However, not everyone has an internet-enabled mobile phone and not everyone will want to download the app, which will be voluntary.