UPDATE 1-Ticketmaster merger referred to UK watchdog

* OFT refers proposed merger to Competition Commission

* Says could restrict competition in ticketing, promotion

(Adds detail, background)

LONDON, June 10 (Reuters) - Britain's consumer watchdog raised antitrust concerns over the planned merger of ticketing company Ticketmaster Entertainment Inc (TKTM.O) with Live Nation Inc (LYV.N), the world's largest concert promoter.

The Office of Fair Trading said on Wednesday it was referring the deal to the Competition Commission, Britain's competition regulator.

The OFT said the merger could reduce competition because the position of CTS Eventim (EVDG.DE), due to replace Ticketmaster as Live Nation's main ticketing agent, would be weakened or it may withdraw from the British market altogether.

The OFT also said the Competition Commission should examine whether Ticketmaster's market position could restrict competition for the promotion of live events.

"It creates a realistic prospect that the merger will deny those attending live music events the benefits of more competition in the distribution of tickets, which could include lower overall prices," said senior OFT director Ali Nikpay. Live Nation agreed early this year to buy Ticketmaster for $400 million in shares but the plan has raised antitrust concerns on both sides of the Atlantic and is being examined by the U.S. Department of Justice.

The Competition Commission is due to report by Nov. 24.

Live Nation and Ticketmaster have said they expect their merger to complete in the autumn. (Reporting by Victoria Bryan; Editing by Dan Lalor)