By Tetsushi Kajimoto

TOKYO (Reuters) - Japan's exports grew for a third straight month in February demand improved in the U.S., China and the European Union, offering some hope for policymakers seeking to revive growth after weak performance last year.

Exports rose 7.8% in February from the same month a year ago, Ministry of Finance data showed on Thursday, faster than the 5.3% gain expected by economists in a Reuters poll.

The trade data comes days after the central bank ditched years of unconventional easing in a shift towards normalising policy.

The Bank of Japan ended eight years of negative interest rates and other remnants of its unorthodox policy on Tuesday, making a historic shift away from decades of massive monetary stimulus. But it is expected to keep rates around zero for some time to support fragile growth.

Exports have been a source of concern for policymakers who worry about the fragile recovery in the world's fourth-largest economy, which narrowly dodged recession late last year.

Imports rose 0.5% year-on-year in February versus the median estimate for a 2.2% increase.

The trade balance came to a deficit of 379.4 billion yen ($2.52 billion), versus a median estimate for a deficit of 810.2 billion yen.

A Reuters monthly poll showed earlier on Thursday that big Japanese firms' confidence rebounded to a three-month high in March while the service-sector mood hit a seven-month high.