The RDS was targeted by hackers during a ransomware attack last week.
The attack happened on February 8 with data was stolen from RDS servers, including "personal data belonging to staff, members, and suppliers".
Hackers then encrypted the data and made it inaccessible to the RDS.
The RDS said the attack is being investigating by IT partners and a specialist cyber security firm is also helping them.
They said in a statement: "This incident is being thoroughly investigated by our IT partners who have taken immediate an appropriate actions to restore our systems, reinforce existing security measures and to mitigate its potential impact, as well as determining its origins.
"The RDS has also engaged the services of a specialist cyber security firm to assist in our recovery from this incident.
"The matter has been reported to An Garda Siochana and the Office of the Data Protection Commissioner has also been notified of this breach pursuant to the GDPR (General Data Protection Regulation)."
The RDS said they have notified everyone whose data was impacted.
"They have been advised to take all necessary precautions going forward. There is no impact on the RDS commercial operations, and we continue to operate as per normal.
"The RDS deeply regrets that this incident has occurred."
Dublin Live has contacted An Garda Siochana for comment.
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