Singapore shares traded lower on Monday morning ahead of a three-day workweek, bucking the trend as other regional indices edged up.

The benchmark Straits Times Index slipped 19.6 points, or 0.6 per cent, to 3,234.5 by 12.20pm.

Stocks that fell outnumbered those that rose 195 to 117, with another 489 counters unchanged.

A total of 1.2 billion shares changed hands, worth $356.7 million in all.

Kuala Lumpur gained 0.1 per cent, Hong Kong was up 0.2 per cent and Jakarta rose 0.4 per cent by midday trading on Monday.