Thousands of Irish passport holders in Northern Ireland who were fully vaccinated there can now access the EU Digital Covid Certificate.
The so-called vaccine passport allows international travel.
The vaccine certificate came into effect in the Republic of Ireland in July but could not be accessed by Irish passport holders north of the border until today.
They can now apply online. Applicants must be over 18 with a valid Irish passport and a Northern Irish Covid vaccination certificate with a QR code issued by the Department of Health at Stormont.
Minister for Health Stephen Donnelly has said he was "delighted" to be able to expand the service.
British passport holders living in Northern Ireland cannot apply for the certificate as the UK has left the European Union.
The service will be expanded further to Irish citizens in non EU countries on 21 October.
Exceptions will be for residents of countries awarded an equivalence decision as the Covid Certificates issued in those states are accepted under the same conditions as the EU Digital Covid Certificate.
To be eligible, a person has to supply proof that they have received a vaccine currently authorised for use in Ireland.
The vaccines which are authorised to date are the Pfizer-BioNTech, Moderna, AstraZeneca and Johnson & Johnson/Janssen vaccines.
The service will be accessible at covidcertificateportal.gov.ie
Over four million Covid certificates have been issued to date under the existing service.
Additional reporting: Fergal Bowers
