Singapore's Straits Times Index rose to its highest point in nearly three weeks on Monday, driven by strong gains across Singapore's major banking stocks, while the city-state's manufacturing output also increased in August.

The Straits Times Index (STI), a key benchmark for the Singapore Exchange, ranged between 5,702.36 and 5,749.66 throughout the day. It ended the session at 5,729.02, up 17.90 points or 0.31% compared to Friday's close.

Singapore's manufacturing output increased 15.4% year on year in August, accelerating from a revised 6.9% increase a month prior, according to data released by the Singapore Economic Development Board.

On the corporate front, shares of Oiltek surged nearly 13% at the close as it submitted an application to the Securities Commission Malaysia for a proposed secondary listing on Bursa Malaysia.

Geo Energy Resources (SGX:RE4) closed nearly 8% higher as it projected a substantial improvement in business operations and a "significant" increase in sales volume and net profit for the third quarter of the year.

Meanwhile, shares of City Developments (SGX:C09), however, fell over 8% at the close as it disclosed the outcome of its strategic review, unveiling a three-year strategy, GET+, from 2027 to 2029.