The main share index gained 0.2 percent, or 11.62 points, to close at 5,794.47, near a three-week high.
Foreign investors were net buyers of 241.6 million rupees ($1.83 million) worth of shares on Tuesday, extending net foreign inflows in equities this year to 19.38 billion rupees.
Shares in Commercial Bank of Ceylon rose 1.57 percent to 116.80 rupees, while shares in top conglomerate John Keells Holdings rose 0.5 percent to 221.10 rupees.
Tuesday's turnover was 816.9 million rupees, less than this year's daily average of about 879.1 million rupees.
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Anupama Dwivedi)
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