The online application system for the European Health Insurance Card (EHIC) has been suspended due to the cyberattack on the Health Service Executive's (HSE) IT systems.
The free card, formerly the E111, gives holders access to necessary, state-provided healthcare during their stay in any of the 27 EU countries as well as Iceland, Liechtenstein, Norway and Switzerland.
The card guarantees healthcare under the same conditions and cost, sometimes free, as people insured in a specific country.
According to the Irish Travel Trade Network (ITTN), the HSE said that the restoration of the web-based processing system for the EHIC is "linked to the general restoration" of HSE services.
They gave no indication of when the system might be restored.
The HSE said that local offices can be contacted by phone and can advise people who need emergency coverage.
All existing EHIC cards are valid until their expiry date, with each card being valid for five years.
The ITTN said it is vital that this system is up and running as soon as possible with Ireland due to resume international travel by July 19.
"The issue of EHIC availability is a critical one, as the card offers insurance cover to all Irish citizens travelling in the EU," the group said.