FILE PHOTO: An Apple logo hangs above the entrance to the Apple store on 5th Avenue in the Manhattan borough of New York City, July 21, 2015. REUTERS/Mike Segar/File Photo

DUBLIN (Reuters) - Apple's AAPL.O main regulator in the European Union, Ireland's Data Protection Commissioner (DPC), has opened a third privacy investigation into the iPhone maker over the last few weeks, a spokesman for the DPC said on Tuesday.

The probe is examining whether Apple has complied with the relevant provisions of the EU’s new General Data Protection Regulation (GDPR) privacy law in relation to an access request from a customer.

It follows investigations opened last year regarding how Apple processes personal data for targeted advertising on its platform and whether its privacy policy on the processing of that data is sufficiently transparent.

The Irish DPC has 20 investigations open into multinational technology companies whose European headquarters in Ireland puts them under its watch, with Facebook FB.O under the most scrutiny with eight individual probes, plus two into its WhatsApp subsidiary and one into Facebook-owned Instagram.

Like Apple, Twitter TWTR.N is also under three different investigations with one each for Google's GOOGL.O, Microsoft MSFT.O owned LinkedIn and U.S. digital advertising company Quantcast.

Under the EU’s General Data Protection Regulation (GDPR), regulators have the power to impose fines for violations of up to 4% of a company’s global revenue or 20 million euros ($22 million), whichever is higher.