SINGAPORE'S benchmark index had its biggest single-day tumble so far this year, in tandem with regional markets as investors were spooked by testimony from US Federal Reserves chairman Ben Bernanke which suggests that the central bank is poised to taper off its money printing action.

The jittery was also exacerbated by news that China's manufacturing output unexpectedly contracted for the first time in seven months.

The Straits Times Index ended 1.8 per cent lower at 3,393.17.