Japan's currency interventions have been stealth operations in order to maximize the effects of its forays into the market, Finance Minister Shunichi Suzuki said on Tuesday, after the government spent a record ¥6.35 trillion ($42.7 billion) supporting the yen last month.

Bank of Japan Gov. Haruhiko Kuroda, however, reiterated the central bank's resolve to keep interest rates ultralow, indicating that the yen's broad downtrend could continue.

Japanese officials remain tight-lipped on exactly when they intervened in the market in October. Full details of their actions will not be available until quarterly intervention data is published. The July-September data is expected to be released early this month.