SINGAPORE (Reuters) - Singapore shares plunged as much as 1.3 per cent to their lowest in nearly five months on Monday, tracking regional losses on fears the United States Federal Reserve might taper its stimulus further and tighter credit conditions in China.

The benchmark Straits Times Index was down 1.3 per cent at 3,036.9 as of midday after declining to 3,025.2, its lowest since Sept 5 and biggest daily decline since Jan 3.

The MSCI's broadest index of Asia-Pacific shares outside Japan fell 1.5 per cent.

Jardine Matheson Holdings and Jardine Cycle & Carriage were the worst performers on the index, with shares falling 3.6 per cent and 4.4 per cent respectively.

Shares of Noble Group dropped as much as 4.7 per cent to a low of $0.91, their lowest in almost four months.

Noble Group announced on Friday its subsidiary Noble Clean Fuels bought a 51 per cent shareholding interest in Watt Power.