Meanwhile, Canadian investment in foreign securities reached a six-month high of $6 billion, led by purchases of U.S. equities.
The agency says foreign investors bought $10.6 billion worth of Canadian debt securities in September, the largest such investment since May.
Foreign investors have acquired $55.8 billion of Canadian debt securities so far in 2012, on par with the level of investment observed for the same period in 2011.
The investment focus, however, shifted to federal bonds in 2012 from federal Treasury bills in 2011.
Canadian investors purchased $4.5 billion of foreign equities in September, the largest such investment since March.
Purchases of U.S. shares strengthened for a third month, to $3.6 billion, led by demand from Canadian pension funds.