Dec. 20 (Bloomberg) -- Japan plans to bolster its intervention war chest to an unprecedented amount, a sign of the government’s vigilance against a yen near postwar highs against the U.S. dollar.

The Finance Ministry plans to raise the issuance limit for bills to fund currency intervention to 195 trillion yen ($2.5 trillion), the first increase since Sept. 30, according to government documents released in Tokyo today. More than 65 trillion yen will be available for additional intervention, according to the ministry.

The measure comes after Japan sold a record amount of its currency in the month from Oct. 28 as the appreciating yen weakens the world’s third-largest economy’s rebound from the March 11 temblor. Finance Minister Jun Azumi said today the increase was needed because he wants to be prepared to take “decisive” actions when needed.

The yen traded at 78.01 per dollar at 12:31 p.m. and rose to a postwar record of 75.35 yen on Oct. 31.

--Editors: Lily Nonomiya, Iain Wilson

To contact the reporter on this story: Toru Fujioka in Tokyo at tfujioka1@bloomberg.net

To contact the editor responsible for this story: Paul Panckhurst at ppanckhurst@bloomberg.net