The benchmark Straits Times Index (STI) fell 0.2 per cent to end at 3,179.13, marking the third consecutive day of decline.
The top gainer on the index was Dairy Farm International, which saw its shares rise 1.9 per cent to close at US$4.39.
Other top gainers include Thai Beverage and Mapletree Logistics Trust, which rose 1.4 per cent and 1 per cent respectively
Finishing at the bottom of the STI performance table on Tuesday was Capitaland, which fell 2.5 per cent to $3.58 as it went ex-dividend.
AEM Holdings was one of the most actively traded stock by value, with 18.3 million shares worth $69.3 million changing hands. The counter fell 6.4 per cent to $3.79, after it reported on Monday a 63.1 per cent decline in its Q1 net profit.
Market watchers noted there were Covid-19 nerves regionally, with sentiment subdued as Covid-19 cases continued to impact India and some South-east Asian countries.
Maybank Kim Eng analyst Kareen Chan said in a note on Monday that it is worth revisiting healthcare stocks such as Riverstone, Medtecs International and Top Glove to hedge the risk, with rising Covid-19 cases and more virulent strains increasingly grabbing headlines.
Elsewhere in Asia, markets were mixed as financial markets in China and Japan stayed closed for a public holiday.
Hong Kong's Hang Seng Index rose 0.7 per cent while South Korea's Kospi and the ASX 200 in Australia both climbed 0.6 per cent on Tuesday. The KLCI in Malaysia fell 0.2 per cent, while the TAIEX in Taiwan fell 1.7 per cent.