MILAN (Reuters) - Atlantia has no plans to buy all of Spanish telecom towers group Cellnex which is controlled by its bid target Abertis, the Italian firm's chief executive Giovanni Castellucci has said.

Motorway and airport operator Atlantia will decide by Friday whether to acquire 29.9 percent of Cellnex, Castellucci told analysts on a March 15 conference call, according to a transcript published by Thomson Reuters StreetEvents.

Atlantia's CEO also told analysts that the Italian group would next year pay a 30 percent increase on top of a 10 percent rise it normally pays to its investors each year, calculating the increase based on the dividend of 0.97 euros/share paid on 2016 results.

Atlantia declined to comment.

"We will never launch a tender offer on Cellnex. We cannot do all this stuff altogether," the Atlantia CEO said.

"The question we will address in the next 10 days is whether we want to keep a significant stake below 30 percent of Cellnex."

Castellucci also mentioned the possibility of finding partners for a deal on Cellnex.

"Cellnex is a big company that can really play the consolidation game," the CEO said.

Under the agreement reached last week with Spanish builder ACS and its German unit Hochtief to jointly buy Abertis, Atlantia has an option to buy between 29.9 and 34 percent of Cellnex by March 23, the Italian group said last week.

Any acquisition breaching a 30 percent threshold in a company will trigger a mandatory tender offer.

Atlantia's CEO also confirmed that the financing package for the acquisition of Abertis would see the acquisition vehicle set up with ACS and its German unit Hochtief issue some debt to repay bank loans.

Sources told Reuters last week a group of banks including Credit Suisse, BNP Paribas, Intesa Sanpaolo, JP Morgan and UniCredit had arranged a 14 billion euro financing for the deal.

(Reporting by Elisa Anzolin and Francesca Landini in Milan, Stefano Bernabei in Rome; writing by Francesca Landini; editing by Jason Neely and Alexander Smith)