The main share index ended 0.23 percent, or 13.61 points, firmer at 6,051.77, recovering from its lowest close since July 19.
Despite the central bank's easing of policy measures, concerns over the weakening rupee and high lending rates have dented sentiment, with investors waiting for directions, brokers said.
John Keells Holdings Plc, which reported a 4 percent drop in June-quarter profits after the market closed, gained 0.75 percent to 269 rupees.
Foreign investors bought a net 87.36 million rupees ($663,600) in shares, extending the year-to-date net foreign inflow to 16.95 billion rupees.
Turnover was 403.8 million rupees, bourse data showed, well below this year's daily average of around 942 million rupees.
($1 = 131.6500 Sri Lanka rupees)
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Subhranshu Sahu)