Thank you for your question, and I apologize for the belated reply. Basically the victims (both from tsunami and the nuclear accident) can postpone the payment of their housing loan, but it is not canceled under the current law.

Since after the Kobe Earthquake, the problem that the victims bear two loans for the lost and new housings is pointed out as "double loan" problem. In the wake of this earthquake, Japan Bank Association and the government announced some new relief measures but it is not popular yet.

Please find the further explanation provided by Japan Federation of 

Bar Association at http://www.nichibenren.or.jp/en/meetings/year/2011/111024.html 

Yoko Matsuda, a member of VfF