Singapore equities snapped two sessions of gains on Tuesday amid caution ahead of the testimony from Federal Reserve Chair Janet Yellen for clues on when the central bank would tighten U.S. monetary policy.
Asian shares were firm, with the MSCI's broadest index of Asia-Pacific shares outside Japan up 0.6 percent.
U.S. stocks closed higher overnight, boosted by technology-led gains.
Chair Janet Yellen will submit Federal Reserve's semi-annual Monetary Policy Report to Congress on Wednesday.
At 0600 GMT, the Straits Times Index fell 0.47 percent or 15 points to 3,231. It ended 0.54 percent higher on Monday, taking the year-to-date gains to 12.7 percent.
Among the losers, chemical maker Jiutian Chemical fell 5 percent while engineering group Miyoshi dropped 3 percent after gains in the previous session.
Commodity trader Noble Group jumped 8 percent after Goldilocks Investment Company raised its stake in the firm.
About 1.1 billion shares worth S$598 million changed hands, with losers outnumbering gainers 202 to 163.