Local investors stayed on the sidelines after the central bank held rates steady, brokers said.
The main share index rose 0.48 percent, or 27.01 points, to 5,704.32, its highest since Feb. 22.
Foreign investors were net buyers of 320.98 million rupees, extending year-to-date foreign inflows to 3.10 billion rupees.
Shares in John Keells Holdings rose 1.19 percent to 237.50 rupees, their highest close since Oct. 13, 2010. The biggest listed lender, Commercial Bank of Ceylon, rose 1.48 percent to a one-month high of 110.00 rupees.
'Foreigners see value in these select blue chips. But the interest rate is playing a major role in local investors' decision making,' said a stockbroker on condition of anonymity.
The central bank last Friday left policy rates unchanged for a third straight month, saying inflation was expected to ease and reach more favourable levels by the end of the year.
The day's turnover was 671.11 million rupees ($5.30 million), well below this year's daily average of 1.06 billion rupees.
The rupee firmed to a one-month closing high of 126.18/28 to the dollar compared with Monday's 126.45/55. ($1 = 126.6750 Sri Lanka rupees)
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Ron Popeski)
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