"It's unavoidable, we'll have large first and second supplementary budgets by June," Kyodo news agency quoted Jun Azumi, a senior Democratic Party member, as telling reporters.

There are no official estimates yet of the economic damage from March 11's 9.0-magnitude earthquake, the strongest in Japan's recorded history, that unleashed masses of water onto its shores and triggered one of the world's worst nuclear accidents.

Private economists expect the economic damage will exceed the cost of the 1995 Kobe quake, reaching as much as $200 billion. Economy Minister Kaoru Yosano told Reuters in an interview the total direct and indirect cost born by the world's third largest economy could top 20 trillion yen $248 billion.

Opposition and ruling party lawmakers are talking about 5 to 10 trillion yen in emergency spending, or as much as 2 percent of the economy, much more than the 3 trillion yen Japan spent in three extra budgets 16 years ago.