British oil major BP is seeking buyers for its 50 percent stake in a Chinese petrochemicals joint venture, its single largest investment in China, in a deal that would fetch $2-$3 billion, people familiar with the matter told Reuters.

BP has hired an investment bank to sell its shareholding in SECCO as part of a drive to cash out of businesses where it lacks control, the people added. A successful deal would mark BP's first significant exit from a business in China.

Situated in Caojing near Shanghai, SECCO is China's largest petrochemicals refinery and was built at a cost of $2.7 billion in 2001, according to BP's website.

State-owned China Petroleum & Chemical Corp (Sinopec) and one of its units hold the other half of SECCO, according to the website.

A London-based BP spokesman declined to comment, and Sinopec did not offer immediate comment.