DAVOS, Switzerland (Reuters) - Business leaders rattled by a slump in global markets appealed to the U.S. and other central banks on Wednesday to get a grip on the global economy and some accused them of losing their nerve.

With share prices tumbling again despite an emergency U.S. interest rate cut on Tuesday to counter fears of recession, top executives expressed alarm as they gathered for an annual meeting in the Swiss resort of Davos.

"Central banks have lost control," said financier George Soros, echoing the concerns of many of the more than 2,000 business and political leaders arriving in the snow-clad mountain town for the World Economic Forum meeting.

In a debate on the U.S. economy, 59 percent of participants agreed with a motion that central bankers had lost control.

Officials from Washington tried to counter the gloom.

"The U.S. economy has sound economic fundamentals," David McCormick, U.S. Undersecretary of the Treasury for International Affairs, said, challenging the view of many around him that a U.S. recession was inevitable.

"While we continue to believe the U.S. economy will grow, it will grow at a slower pace and there is no doubt downside risks have increased," he said.

But many executives said the surprise decision by the U.S. Federal Reserve on Tuesday to cut interest rates by 75 basis points looked like a panic move.

"I'm sort of worried that all they did yesterday was to hit the snooze button. (This is) excessive monetary accommodation that just takes us from bubble to bubble to bubble," said Stephen Roach, Asia head of U.S. bank Morgan Stanley.

Lawrence Summers, a former U.S. treasury chief, was critical too: "It's hard to give a high grade (to central banks) for what's happened in the last six months."

Another former head of the U.S. Treasury, John Snow, was more supportive of the U.S. central bank.

"What yesterday's action shows us is the Fed is focused but they are aware of negative trends in the economy and prepared to take bold steps," he said.

FIRESIDE SPAT

Business and political leaders gathering in Davos face what many fear could be the biggest financial crisis since World War Two.

The emergency U.S. interest rate cut on Tuesday, after two days of plummeting stock prices, set the tone for the WEF meeting where financial, industrial and political figures, including U.S. Secretary of State Condoleezza Rice, are awaited.

Policymakers accustomed to relaxed chats in the winter splendor of the Swiss Alps will this year face a more torrid time as business leaders fret over the outlook.

"The thing that markets are desperate for right now is leadership, whether globally or regionally, and it seems this is lacking," said John Studzinski, head of U.S. private equity firm Blackstone's advisory business.

But other business leaders said even if the U.S. economy began to shrink, the impact for the rest of the world would be less than in the past, thanks to the booming economies of developing countries such as China and India.

"I think there is certainly better than 50 percent chance that the U.S. is headed into a recession," Coca-Cola Co. Chief Executive Neville Isdell told Reuters.

"But does this signal we are going to have significant contagion around the world, which means we are going into a global recession? I don't believe that is the case," he added.

Martin Sorrell, CEO of the world's second-biggest advertising and marketing company WPP Group Plc, said he saw no sign of a slowdown in his bellweather industry, although 2009 might be a different picture.

"We as an industry probably would be a lead indicator of recession and I think it is interesting that we have not seen a significant shift in purchasing intention in the advertising and marketing services industry as yet," he said.

The Fed's unilateral action on Tuesday, when it cut rates by 75 basis points, was its biggest emergency cut in two decades.

It has put more pressure on the European Central Bank to relax its view against cutting rates and coordinate a response.

But ECB chief Jean-Claude Trichet, speaking in Brussels on Wednesday before departing for Davos, refused to buckle, saying low inflation remained the bank's priority.

For full coverage, blogs and TV from Davos, see: http://uk.reuters.com/news/globalcoverage/worldeconomicforum2008

(Additional reporting by the Davos news reporting team; editing by Ralph Boulton)