Facebook says that more than 44,000 people in Ireland may have had their personal data improperly shared with Cambridge Analytica.
Yesterday, the social network admitted that 87 million users around the world may have been affected by the controversy - which revolves around claims data from a personality test app was improperly shared with the UK-based political consultancy firm.
Facebook says the vast majority of those impacted are believed to have been in the US.
However, the company added: "We do know that 15 people in Ireland installed thisisyourdigitallife, and up to 44,687 people in Ireland may have been friends with someone who installed the app, and, therefore, may have been affected."
Facebook says anyone potentially impacted will be informed shortly.
Facebook CEO Mark Zuckerberg has admitted his company didn't do enough to prevent abuse of the platform.
He said: "We didn’t take a broad enough view of what our responsibility is, and that was a huge mistake. It was my mistake."
Cambridge Analytica - which is known for its work with groups such as Donald Trump's presidential campaign - has insisted it immediately deleted data when it was informed the information may have been improperly obtained.
It also says none of the data was used during the 2016 US election, and dispute the Facebook and media estimates of the number of people impacted.
Cambridge Analytica licensed data from GSR for 30 million individuals, not 87 million. We did not receive more than 30 million records from research company GSR.
— Cambridge Analytica (@CamAnalytica) April 4, 2018