Fota Wildlife Park in Cork has said that all customers potentially impacted by a cyberattack have now been contacted.
The park has not yet said how many people may have had their financial information compromised by the hack.
A dedicated phoneline has been established, which will operate today and tomorrow, for people who have concerns about their data.
On Wednesday, Fota Wildlife Park said it had been hit by a cyberattack and urged customers to cancel credit and debit cards that had been used to make payments on its website between 12 May and 27 August.
External forensic cyber security experts have been engaged to investigate the incident.
The Data Protection Commission and gardaí have also been notified.
"If you have a user account on the Fota website, the username, password and email address linked to that account may have been accessed," Fota said in an email to customers.
Fota said it is strongly recommending that customers cancel credit or debit cards that have been used to make payments on the park's website.
Customers are also being urged to review relevant bank account and credit card statements since 12 May, to identify potential suspicious activity.
Fota Wildlife Park said its day-to-day operations continue as normal and the park remains open to visitors with tickets available for purchase on entry to the park.
Fota's website remains offline with a notice on its homepage containing details of the dedicated helpline which can be reached at 021 203 3903.
Fota Island Resort has said it is aware of the cyberattack at Fota Wildlife Park, but stressed that it is a separate business and not impacted.
