The market also awaited the release of the federal budget for 2013 on Thursday and if the government planned measures to support the economy.
The Colombo Stock Exchange's main index rose 0.26 percent, or 14.28 points, to end at 5,570.87, its highest level since Oct.25.
Shares of John Keells Holdings PLC gained 0.24 percent to 213.20 rupees.
"All are awaiting to see the budget," said a stockbroker, who declined to be identified. "We have seen some foreign buying and hope it will pick up slowly now."
Turnover was 250.6 million rupees ($1.92 million), less than a quarter of this year's daily average of 911 million rupees. Foreigners bought a net 40.1 million rupees worth of shares, extending the net foreign inflow this year to 34.6 billion.
The rupee weakened to 130.85/95 to the dollar from Tuesday's close of 130.65/75 on importer dollar demand, dealers said. ($1 = 130.7000 Sri Lanka rupees)
(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Sanjeev Miglani)
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