Core consumer prices in Tokyo, a leading indicator of nationwide trends, rose 4.3% in January from a year earlier, marking the fastest annual gain in nearly 42 years and keeping the central bank under pressure to phase out economic stimulus.

While the government's energy subsidies starting next month will likely moderate price gains from February, the data heightens the chance that inflation will stay well above the Bank of Japan's 2% target in coming months as companies continue to steadily pass on higher costs to households.

The rise in the Tokyo core consumer price index (CPI), which excludes fresh food but includes fuel, exceeded a median market forecast for a 4.2% gain and marked the fastest year-on-year increase since May 1981.