The Bank of Japan, which has struggled to return the country to growth, said it will cut short a two-day policy review scheduled for next week to one day Monday and promised to do its utmost to ensure financial market stability.
Auto plants, electronics factories and refineries shut, roads buckled and power to millions of homes and businesses was knocked out. Several airports, including Tokyo's Narita, were closed and rail services halted. All ports were shut.
Japan's biggest quake on record occurred as the world's third-largest economy had been showing signs of reviving from an economic contraction in the final quarter of last year.
The disaster raised the prospect of major disruptions for business and a repair bill of billions of dollars.
Leaders of the ruling and opposition parties agreed on the need for an extra budget after Prime Minister Naoto Kan asked them to "save the country," Kyodo news agency reported.