* Japan to lay out fiscal reform around mid-year - Noda
* Gained G20 understanding on Japan recovery - Shirakawa
* BOJ to maintain ultra-easy policy - Shirakawa (Adds quotes, details)
By Leika Kihara
WASHINGTON, April 15 (Reuters) - Japan will lay out a medium-term plan for fiscal reform when it crafts a second extra budget for reconstruction around mid-year, the finance minister said, aiming to dispel market concern that last month's devastating earthquake may delay the country's efforts to rein in its huge public debt.
Bank of Japan Governor Masaaki Shirakawa said he has vowed to his Group of 20 counterparts that the central bank will keep monetary policy ultra-loose to support an economy hit hard by the March 11 earthquake.
"I explained that once the current severe supply constraints ease, Japan's economy will gradually resume a recovery. I think we gained our counterparts' understanding," Shirakawa told a news conference on Friday, after the G20 finance leaders' gathering.
Finance Minister Yoshihiko Noda told the same news conference the government's near-term priority was to pass through parliament an initial extra budget for disaster relief, which is set to exceed 4 trillion yen ($48 billion).
While the first emergency budget will not involve issuance of fresh bonds, a "significant amount of funds" may be needed for the second extra budget for reconstruction, Noda said.
Even so, the government needs to be mindful of "people who worry whether Japan will stray away from fiscal discipline", he said, cautioning against issuing bonds easily with Japan's public debt already twice the size of its $5 trillion economy.
"The government should lay out its medium-term fiscal reform plan at the same time it compiles the (second) emergency budget for reconstruction," Noda said, signalling that the roadmap for fiscal reform should be issued around mid-year.
Japan is facing its worst crisis since World War Two after a 9.0 magnitude earthquake and a tsunami battered its northeast coast last month, crippling a nuclear power plant and disrupting factory output with supply disruptions and power shortages.
The government estimates the material damage alone could top $300 billion, making it by far the world's costliest natural disaster, but analysts say the cost may be much higher.
The negative impact of the quake was cited as among the downside risks for the global economy in a G20 communique issued on Friday, although Noda and Shirakawa stressed that Japan's economy can overcome the challenges posed by the disaster.
Some lawmakers have called on the government to spend big and issue bonds to finance the costs to support the economy, although Noda has been cautious of doing so on concern of scaring investors already wary of Japan's huge debt pile. ($1 = 83.510 Japanese Yen) (Editing by Edmund Klamann and Alex Richardson)