Italy's Antitrust Authority has launched an official probe into publishing giant Seat Pagine Gialle's take-over of broadcaster Telemontecarlo.

Seat, which is currently swallowing Telecom Italia's internet division, agreed in August to purchase 75% of TMC from the Cecchi Gori Group, for L750bn ($335m), with an option to up its stake to 100%.

"The operation must be evaluated by taking into account the activities of the Telecom Italia group which Seat has joined," the authority said, after examining the case put forward by Seat and Telecom Italia over the course of the last two months.

Referring to an Italian law which forbids Telecom Italia or any company it controls from owning a free-to-air TV network, the watchdog added: "This represents the first case in Italy of a convergence between telecommunications and broadcasting."

When the takeover deal was originally announced, it sparked protests from opposition leader Silvio Berlusconi who owns rival television group Mediaset. But Communications Minister Salvatore Cardinale said the government approved of Seat's proposal to buy TMC, since a third TV force would boost competition in Italy and bring advantages to consumers. The watchdog has said it will complete its investigation within 45 days.