UPDATE 1-WTO sees postwar record 9 pct drop in world trade

* World trade to fall 9 pct this year as recession strikes

* Biggest contraction since World War Two

GENEVA, March 23 - Trade volumes will fall 9 percent this year, the biggest contraction since World War Two, as demand collapses in the biggest economic downturn in decades, the World Trade Organisation (WTO) said in a report.

The forecast -- much steeper than the 2.8 percent fall forecast by the International Monetary Fund in January -- underlined the scale and rapid worsening of the economic crisis faced by leaders of G20 countries when they meet next week.

"Trade can be a potent tool in lifting the world from these economic doldrums," WTO Director-General Pascal Lamy said.

"In London G20 leaders will have a unique opportunity to unite in moving from pledges to action and refrain from any further protectionist measure which will render global recovery efforts less effective," he said in a statement.

The volume of developed country exports will fall 10 percent this year, while trade-dependent developing countries will see export volumes shrink by between 2 and 3 percent, the WTO said.

World trade tapered off sharply in the second half of 2008 to show growth of 2 percent over the whole year, after rising 6 percent in 2007, it said.

The report was originally scheduled to be released on Wednesday, but several media organisations published it on Monday.