UPDATE 2-German court turns to top European judges for help on Facebook data case

(Adds reaction from German cartel office)

By Matthias Inverardi

DUESSELDORF, March 24 (Reuters) - A court in Germany hearing an appeal by Facebook against data curbs imposed by the country's antitrust watchdog said on Wednesday it would seek guidance from the European Court of Justice on the case.

The move effectively defers a verdict in the two-year-old court battle and casts a spotlight on whether Germany's Federal Cartel Office may have exceeded its authority in seeking to apply competition law to the issue of data protection.

In the European Union, of which Germany is the largest member, issues around technology and personal privacy are covered by a rulebook introduced in 2018 called the General Data Protection Regulation (GDPR).

"The question of whether Facebook is abusing its dominant position ... cannot be decided without referring it to the European Court," the Higher Regional Court in Duesseldorf said in a written opinion.

Cartel office chief Andreas Mundt ordered Facebook in February 2019 to curb its data collection, saying the world's largest social network had abused its market dominance to harvest the information of its users without their consent.

This included gathering data about users' browsing habits when they visited a website with a Facebook 'like' button on it - even if an internet surfer didn't click on that button.

Facebook appealed that decision and, in the last significant development in the case, the German Federal Court reinstated the restrictions last June pending a resolution of the high-stakes legal battle.

The cartel office expressed disappointment the Duesseldorf court's referral would delay a final verdict by a higher court. "We of course regret this in light of the support that our decision had received ... from the Federal Court," it said.

In its opinion, the panel of judges chaired by Juergen Kuehnen found fault with Facebook over its collection of data on the social network and other applications, including WhatsApp, Instagram and Oculus.

But it also questioned whether the cartel office exceeded its remit, whether it had incorrectly targeted different Facebook corporate entities, and whether it had given the company a fair hearing before acting.

"The Higher Regional Court today expressed doubts about the legality of the Federal Cartel Office's decision and decided to refer questions to the European Court of Justice," Facebook said in a statement.

"In our opinion, the order of the Federal Cartel Office also violates European law." (Reporting by Matthias Inverardi. Writing by Douglas Busvine. Editing by Emma Thomasson and Mark Potter)