BRUSSELS (Reuters) - European Union antitrust regulators have opened an in-depth investigation into whether U.S. drinks can maker Ball Corp's (>> Ball Corporation) 4.4 billion pound offer for Britain's Rexam Plc (>> Rexam PLC) will lead to higher prices for companies and consumers.

The deal, announced in February, would combine the world's two largest beverage can makers by volume, controlling just over a fifth of the global market and serving clients such as Coca-Cola Co (>> The Coca-Cola Co) and Anheuser-Busch InBev SA (>> ANHEUSER-BUSCH INBEV).

But the European Commission said on Monday it had concerns the combination would likely result in price increases for businesses and therefore consumers.

"Very many of us buy drinks in cans ... it is therefore very important that the Commission makes sure that Ball's takeover of Rexam does not restrict effective competition and so risk price increases that could be passed on to consumers," Margrethe Vestager, EU Competition Commissioner, said in a statement.

The Commission will now decide by Nov. 25 whether to clear the deal.

It said the high entry barriers in the industry because of the need to ensure large customer orders and invest in building production plants made fast entry and expansion difficult.

Its decision to open a full-scale investigation could ramp up the pressure on Ball to offer concessions to counter regulatory concerns.

Antitrust experts said these could include selling overlapping assets in various EU countries to rivals such as Crown Holdings Inc (>> Crown Holdings, Inc.).

(Editing by Robin Emmott and David Holmes)

By Foo Yun Chee and Julia Fioretti