Foreign investor holdings in government bonds rose to 225 billion rupees in the week ending February 29, up from 212 billion rupees a week earlier.
Treasury bill holdings rose to 91 billion rupees from 84 billion rupees a year earlier.
The bill holding has tended to fluctuate from week to week.
Sri Lanka's government bonds yield over 10 percent a year and the rupee fell from around 110 to 120 following several months of sterilized interventions.
The central bank has said interventions may continue for at least two to three months for about 850 million US dollars.