The Bank of Japan refrained from bolstering its record monetary stimulus as policymakers gauge the impact of the negative interest rate strategy they adopted in January.

At a two-day meeting that ended Tuesday, the central bank's Policy Board downgraded its assessment of the economy, saying that the pickup in exports has paused.

Gov. Haruhiko Kuroda and his board kept the target for increasing the monetary base unchanged, and left their benchmark rate at minus 0.1 percent, the BOJ said Tuesday. The decision was forecast by 35 of 40 economists surveyed by Bloomberg. The central bank reiterated that it will add easing if necessary.