The Asian Development Bank will revise its growth projections for the region as the impact of the global economic crisis may be worse than earlier expected.

"We knew the crisis was coming; but perhaps we underestimated how hard it would hit," ADB president Haruhiko Kuroda said at the Special Association of Southeast Asian Nations + 3 Finance Ministers' Meeting in Thailand.

Kuroda cited continued financing constraints and weakening business sentiments as the global downturn is becoming more severe and prolonged. He highlighted that the richest countries are all in recession, prompting the International Monetary Fund to project a mere 0.5 percent growth for the world economy in 2009.

"We clearly  have not reached bottom. And worse, we don't know what's lurking around the corner," Kuroda said.

"Things move pretty fast, and our flagship Asian Development Outlook will update - and no doubt lower - our forecasts on March 31," Kuroda said.

In December 2008, the ADB projected that growth in emerging Asia would slow to 5.7 percent in 2009, down from an earlier estimate of 6.9 percent.