London: Ireland's data regulator on Monday slapped Facebook owner Meta with a 265-million-euro (USD 275 million) fine after details of more than half a billion users were leaked on a hacking website.

The penalty resulted from an investigation, started in April 2021, related to the discovery of a collated dataset of Facebook personal data that had been made available online. Facebook was also ordered to take a range of corrective measures, reported Euronews.

Meta said it had cooperated fully with the investigation by Ireland's Data Privacy Commissioner (DPC) and made changes to its systems during the time in question, including removing the ability to scrape its features in this way using phone numbers.

Monday's fine is the fourth that Ireland's Data Privacy Commissioner (DPC) has levied against one of Meta's companies. It is Meta's lead privacy regulator within the European Union and has 13 more inquiries into the social media group outstanding.

The DPC regulates Apple, Google, Tiktok and other technology giants due to the location of their EU headquarters in Ireland. It currently has 40 inquiries open into such firms, including the 13 involving Meta, reported euronews.

The regulator has the power to impose fines of up to 4 per cent of a company's global revenue under the EU's General Data Protection Regulation's (GDPR) "One Stop Shop" regime introduced in 2018.

The DPC said mitigating factors in Monday's decision - which had been approved by all other relevant EU regulators - included Facebook's actions.

In September the watchdog hit its Instagram subsidiary with a record fine of 405 million euros, which Meta plans to appeal.

The Irish regulator said in a statement that other relevant EU regulators agreed with the decision issued on Monday after it shared a draft ruling with them last month under the bloc's "one-stop shop" system of regulating large multinationals.