Luxottica, the world's largest spectacles manufacturer, completed this week its merger with France's Essilor, the biggest lens maker globally.

The Italian group in June announced it had bought Barberini, the world's top manufacturer of optical glass sun lenses, in a 140 million euro ($161 million) deal.

The antitrust said in a document on its website EssilorLuxottica and Barberini would control 65-70 percent of the Italian sunglasses market.

"Barberini's positioning ... leads one to believe that such a concentration could significantly hamper competition ... creating or strengthening a dominant position," it said.

Luxottica had no immediate comment.

(Reporting by Alberto Sisto, writing by Valentina Za)