Ireland’s Data Protection Commissioner will be investigating Facebook’s data transfers which it had previously called "vexatious and frivolous".
The complaint, lodged by Austrian privacy activist Max Schrems, claims that the social networking giant "aids US spy agencies [with] mass surveillance."
The Irish regulator’s change of decision follows a European court ruling that has kickstarted a diplomatic row between the US and the European Union.
The ruling by the European Court of Justice earlier in the month had confirmed Schrems’ complaint and declared the Safe Harbour trade pact which governs data transfers between the EU and the US to be invalid.
Data Protection Commissioner Helen Dixon said: "My Office will now proceed to investigate the substance of the complaint with all due diligence."
The European Court ruling holds the Irish regulator responsible for the investigation since Facebook has its international headquarters at Dublin.
