BRUSSELS, Feb 10 (Reuters) - Europe's top court on Tuesday sent Meta Platforms META.O unit WhatsApp's fight against the EU privacy watchdog back to a lower tribunal, prolonging a five-year tussle triggered by the latter's order to the Irish data protection authority to jack up a fine to 225 million euro ($268 million).

"The action brought by WhatsApp Ireland against Binding Decision 1/2021 of the European Data Protection Board is admissible," the Luxembourg-based Court of Justice of the European Union said.

The Irish privacy enforcer ratcheted up its fine against WhatsApp in 2021 after the European Data Protection Board (EDPB) intervened.

Meta subsequently appealed the penalty at a lower tribunal but lost after judges said the company was not directly concerned by the EDPB decision and that the Irish watchdog had some discretion on its final decision.

The case is C-97/23P Whatsapp Ireland v EDPB.

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(Reporting by Foo Yun Chee and Sudip Kar-Gupta; editing by Philip Blenkinsop)

((foo.yunchee@thomsonreuters.com; +32 2 585 2866; Reuters Messaging: foo.yunchee.thomsonreuters.com@reuters.net/))