SINGAPORE (Reuters) - Singapore shares were headed south on Wednesday, on course for their biggest decline in more than a week, as worsening tensions in Ukraine weighed on investor sentiment in the region and curbed risk appetite.

The benchmark Straits Times Index fell 0.4 per cent to 3,231.60, while MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.8 per cent.

The losses were led by Golden Agri-Resources and Thai Beverages, as both dropped 1.6 per cent.

Shares of marine and offshore engineering group Sembcorp Industries were flat, after gaining in early trading after the company's earnings report on Tuesday showed first-quarter net profit rose 5 per cent from the same period last year.

OCBC maintained its "buy" rating on the Sembcorp stock while lowering the target price to $6.17 from $6.42, citing expectations of a steady performance amid intense competition in the Singapore power market.

"Going forward, Sembcorp Industries's pipeline of projects is expected to increase its power capacity by more than 70 per cent and its water and wastewater treatment capacity by more than 20 per cent over the next three years, enhancing recurring earnings," the brokerage said in a note on Wednesday.