Dec 12 (Reuters) - The European Union is set to probe Formula One owner Liberty Media's 3.5 billion euro ($3.67 billion) deal for the motorcycle racing league MotoGP World Championship, Bloomberg News reported on Thursday, citing people familiar with the matter.

The new EU antitrust chief Teresa Ribera's team is worried that the merger could stifle competition in broadcasting and streaming sectors by bringing two major motorsports brands under a single umbrella, the report said.

Liberty Media did not immediately respond to a Reuters request for comment.

The company said in April that it would acquire about 86% of MotoGP's parent company Dorna, with Dorna management retaining around 14% of its equity, giving the deal an enterprise value of 4.2 billion euros for Dorna/MotoGP and an equity value of 3.5 billion euros.

Officials are preparing to initiate a phase 2 investigation by the current deadline of Dec. 19, the Bloomberg News report said, adding that the decision is still in draft form and subject to change.

Liberty Media in 2016 struck a deal to buy Formula One from a consortium of sellers led by CVC Capital Partners for $4.4 billion.

Last month, Liberty Media announced the spinoff of most of its assets, excluding Formula One and other related sports investments, as it looks to sharpen focus on its motorsports businesses.

Under the leadership of Chairman John Malone, Liberty Media has acquired a wide network of media, communications and entertainment business including a significant stake in U.S. concert promoter Live Nation Entertainment .

($1 = 0.9528 euros)

(Reporting by Harshita Mary Varghese in Bengaluru; Editing by Maju Samuel)

((HarshitaMary.Varghese@thomsonreuters.com;))