REUTERS - Singapore shares slightly fell on Wednesday, with Golden Agri-Resources among the biggest decliners on concerns about a weaker crude palm oil outlook.

The Straits Times Index was down 0.2 per cent at 3,239.29, largely in line with the MSCI Asia-Pacific ex-Japan index.

Golden Agri shares dropped as much as 4.6 per cent to $0.52, their lowest since May 6.

More than 141 million shares were traded, 3.4 times the average full-day volume over the past 30 days. The company will report its second-quarter results on Friday.

"There will be more soybean supplies going into the later part of this year with United States planting so far doing quite well,"said Ivy Ng, an analyst at CIMB Research.

"Soybean oil is a substitute for palm oil, so there is a concern that palm oil could lose its competitive edge against soybean oil. To keep palm oil competitive, the prices are a bit under pressure."

Shares of oil exploration firm Rex International Holding surged as much as 18 percent above its initial public offering price of $0.50. The company said the public tranche of its offering was 153 times subscribed.

The stock hit an intra-day of $0.59 with nearly 90 million shares traded.