Activist investor Starboard Value LP said on Friday that it planned to vote in favor of the $4.7 billion offer for Smithfield Foods Inc (SFD) by China's Shuanghui International, saying it has not been able to line up an alternative proposal.

Starboard, which has a 5.7 percent stake in Smithfield, the world's largest pork producer, has criticized the deal. The transaction needs the approval of just over 50 percent of Smithfield shareholders at a special meeting next Tuesday, Sept. 24.

Starboard said in a filing with the U.S. Securities and Exchange Commission that unless another proposal emerged, it would vote for the Shuanghui deal.

"While we are confident that (Smithfield) could have received value in excess of that available pursuant to the proposed merger, we are not able to offer shareholders an alternative proposal at this time," Starboard said in the filing.

The deal, struck in May, would be the biggest takeover of a U.S. company by a Chinese one.

Sources earlier this week told Reuters that Shuanghui was already well on its way to crossing the 50 percent threshold and was optimistic it would be able to close the deal by Sept. 26.

Smithfield shares were down 0.6 percent at $33.97 on Friday morning, close to Shuanghui's $34 per share offer.

A Smithfield spokeswoman declined to comment. A Starboard spokesman did not immediately respond to a request for comment.