TOKYO (AFP) - The Bank of Japan's new governor Haruhiko Kuroda on Thursday pledged "all-out efforts" to rid Japan of growth-sapping deflation as gloomy new trade data underlined the scale of the task ahead.

Kuroda, a finance veteran who supports aggressive monetary easing, told Prime Minister Shinzo Abe he would do his best to revive the world's third-largest economy.

"I said that I will make all-out efforts... to pull Japan's economy out of deflation," Kuroda said after a morning meeting with the premier.

The 68-year-old former Asian Development Bank president conceded there would be "difficulty ahead" in rebooting Japan's economy and reversing years of falling prices that have crimped private spending and corporate investment.

But "we must achieve it and I believe it can be achieved", Kuroda told reporters at his first official press briefing on Thursday evening.

The Oxford university graduate declined to say if he would call a rate-setting policy board meeting before the next scheduled meeting in April.

The yen strengthened against the dollar and euro after his comments disappointed expectations of imminent easing measures.

"I know emergency meetings have been held in the past so it is not impossible," Kuroda said.

The government and central bank have faced criticism overseas, particularly in Europe, that they engineered a decline in the yen in recent months through monetary policy, risking setting off a global currency devaluation war.

Kuroda denied those claims Thursday, saying "monetary policy is not meant to target forex rates, which are affected by many factors".

Kuroda is a longtime critic of the Bank of Japan, saying it has been too timid in its approach to fuelling economic growth.

But he has hailed a two-per cent inflation target aimed at tackling deflation - seen as more explicit than a previous "goal" - adopted by the central bank's previous chief in January.