Work is "ongoing" to ensure that Irish passport holders living in Northern Ireland will be able to access the EU Digital Covid Certificate, with the issue being raised at a meeting of the North South Ministerial Council.
Speaking after the meeting, Northern Ireland Deputy First Minister Michelle O'Neill said she welcomed "the fact that there is ongoing work to resolve the issue".
"I don't have a timeframe to speak of at this stage but I know that at an official level in terms of data sharing, there is ongoing conversations, so I hope that that issue will be resolved as soon as is physically possible," she said.
She said there should be no barriers to EU citizens in Northern Ireland having access to the EU Digital Covid Certificate.
The certificates show the holder is fully vaccinated, has tested negative for Covid-19 or has recovered from the disease.
Currently, most Irish passport holders in Northern Ireland cannot access the certificate due to having been vaccinated outside of the Republic of Ireland.
"There's no barrier to people living across the island being able to access hospitality. The vaccine certs that have been issued in the north, in terms of their card etc, will be acceptable," Ms O'Neill said.
Taoiseach Micheál Martin, who hosted the virtual meeting, said: "In terms of the Digital Covid Certificate, there's absolutely no issue in terms of people accessing hospitality with the certification they already have, in terms of the vaccination in the north.
"We've put our two chief information officers together and officials to work through whatever operational issues in terms of the sharing of data and so forth. That work is continuing."
Tánaiste Leo Varadkar and a number of cabinet ministers were in attendance, as were a delegation from the Northern Ireland Executive led by First Minister Paul Givan and Ms O'Neill.
The 26th NSMC had been due to take place in June, however it was cancelled following Edwin Poots' resignation as leader of the DUP.