Warner Music Group and independent labels have urged EU regulators to fight Sony Corp's bid to buy out Michael Jackson's stake in its music publishing joint venture, saying the move gives Sony too much power.

Sony last month signed a deal to acquire the stake that deceased pop star held in Sony/ATV Music Publishing, the world's largest music publisher, which owns copyrights to most of the Beatles' songs and songs by the Rolling Stones, Taylor Swift, Pharrel Williams and Kanye West. [nL3N16N029}

Warner Music Group -- Sony's rival -- has expressed its concerns to the European Commission, said a person familiar with the matter, who declined to be named because of the sensitivity of the issue.

"This gives Sony complete control of both parts of the business, the music recording and the music publishing. They would have more than 50 percent of the market in Europe," the person said on Thursday.

"The deal should be blocked or the company make appropriate undertakings."

Lobbying group Impala, which represents independent labels and national trade associations, expressed the same worries.

"It will increase their market power via control shares. In a nutshell they will have more negative power over more music and the EU already flagged that as a problem before, when it cut Sony back when it bought EMI," Impala's executive chair Helen Smith said.

Sony had to sell the worldwide publishing rights to four catalogs and the musical works of 12 artists including Robbie Williams and Lenny Kravitz in return for EU consent to buy EMI's music publishing businesses in 2012.

Commission spokesman Ricardo Cardoso declined to comment. Sony had no immediate comment and Warner did not immediately reply to an email for comment.