Foreign investors have turned to net sellers of South Korean stocks in June on concerns over a looming interest rate hike in the U.S. and continued Greek debt standoffs, data showed Thursday.

Offshore investors sold a net 859.6 billion won ($769.6million) in the main KOSPI market for seven trading days starting June 8, according to the data compiled by the Korea Exchange, the main bourse operator.

They dumped a net 311.1 billion won worth of shares Tuesday, marking the biggest selling in five months. The benchmark index KOSPI dipped 0.7 percent on the day.

Foreigners have snapped up nearly 10 trillion won of local shares this year, helping push up the local equity market.

Market watchers expected foreigners may remain net sellers for a while as the U.S. Federal Reserve is on track to raise interest rates as early as September.

"The U.S. Fed could give a signal for an interest rate hike in September in the upcoming meeting of the Federal Open Market Committee," said Ji Ki-ho, a researcher at LIG Investment & Securities.

Some pointed out that subdued hope for second-quarter earnings of major exporters lessens appeal of their equities.

"Foreign buying has recently declined as earnings estimates for the auto, IT, shipbuilding and transportation industries have inched down," said Kang Bong-joo, a researcher at Meritz Securities. (Yonhap)