Singapore shares tumbled 0.36 per cent by midday on Tuesday, with the Straits Times Index dropping 11.69 points to 3,225.13 by 12.15pm.

A total of 1.1 billion shares valued at $389 million were done in morning trading.

Losers led gainers 155 to 135, with 507 counters unchanged.

Among the gainers was Keppel Corp, up five cents to $10.89, while OCBC Bank was among those who lost ground, dipping six cents to $10.28.