UPDATE 3-IADB seeks huge capital hike, U.S. backs review

* IADB urged to increase capital by $150 bln-$180 bln

* Bank's loan requests seen way above $20 billion in 2009

* US backs review to hike bank capital-Geithner (Recasts with comments from Geithner)

By David Lawder and Daniel Bases

MEDELLIN, Colombia, March 29 (Reuters) - The Inter-American Development Bank on Sunday weighed hiking its capital by up to $280 billion to help the region weather the global financial crisis and won cautious backing from key shareholder the United States.

The IADB, one of the region's top lenders, held its annual meeting in Medellin as Latin American financial leaders are struggling to tackle the world slowdown, which has battered exports and slashed prices of their commodities.

The IADB is seeking to bolster its capital from $101 billion after last increasing its funds in 1994-1995. This year it expects to lend $18 billion, including $6 billion from an emergency fund, but member demand could be much higher.

U.S. Treasury Secretary Timothy Geithner told the IADB's annual assembly the United States was prepared to start a review of a permanent capital increase, but first it should try to maximize its existing resources.

"We believe there is additional room to expand your balance sheet and deploy additional resources to help governments in the region," Geithner said.

The United States is the largest shareholder in the bank, with a 30 percent voting share.

The IADB summit comes just before leaders of the world's 20 largest economies meet on Thursday to debate how stricter regulation of financial markets, stimulus measures and trade finance can spur world economic recovery after the sharpest downturn in decades.

IADB President Luis Alberto Moreno said the governors of the bank have reached a consensus to increase its capital but that a formal agreement is still being negotiated.

In the last five years development loan requests to the bank averaged $7 billion annually, but have increased sharply this year, said Pedro Pablo Kuczynski, a former Peruvian prime minister heading the IADB commission reviewing its needs.

"If you were to add up what everybody is talking about, you would be way above $20 billion for this year, for 2009. For 2010, probably the same, again," he said.

The World Bank said on Friday Latin America and the Caribbean region face zero growth this year and an increasing probability of contraction as the global crisis batters their exports, commodity prices and remittances.

CHINESE SUPPORT