Japan's consumer inflation held steady above the central bank's target in March and an index excluding fuel costs rose at the fastest annual pace in four decades, data showed, indicating broadening price pressure in the world's third-largest economy.

The data may keep alive market expectations that the Bank of Japan could begin to phase out a massive stimulus program later this year that has drawn public criticism for distorting bond markets and crushing financial institutions' margins.

"Inflationary pressure is proving stronger than expected and could last for longer than thought," said Shinke Yoshiki, chief economist at Dai-ichi Life Research Institute.