TOKYO (Reuters) - New York-based hedge fund company Third Point said on Tuesday that it had raised its stake in Sony Corp and asked for an opportunity to present its proposal for a partial spin-off of the company's entertainment unit to Sony's board.

In a letter to Sony Chief Executive Kazuo Hirai, Third Point said it had increased its stake in Sony to 70 million shares, valued at $1.4 billion.

"Given our large stake, we reiterate our offer to serve on Sony's board of directors," the fund said in its letter reviewed by Reuters.

(Reporting by Chikafumi Hodo; Editing by Chris Gallagher)