(Reuters) -- The world economy will lose momentum in 2012 but it will keep moving in the right direction, according to Reuters polls of around 600 economists who said crisis-hit Europe would drag on global growth.

Asian economies will again power the expansion of the world economy this year, but with relatively subdued performances. The

United States, meanwhile, should continue to contribute modest growth that will easily outpace its recession-hit European peers.

Brazil will be one of the few big economies that will pick up steam this year, outshining slower Latin American stablemates Mexico and Argentina.

A Reuters poll that covers all of the top 20 developed and emerging economies, as well as some others in Asia, suggests global economic growth will slow to around 3.3 percent this year from an estimated 3.7 percent in 2011.

That is more optimistic than the latest forecast from the World Bank, which predicted world GDP would rise only 2.5 percent this year.

Although the euro zone's sovereign debt crisis represents a huge risk to the world's economic health, there have at least been promising signs of life from the United States.

We're fairly optimistic on the U.S., and we're in the soft-landing rather than the hard-landing camp for China, said Investec economist Victoria Cadman, whose forecast for global growth in the high-three percent range is slightly more optimistic than the consensus.

(That's) notwithstanding the huge risks that the euro crisis poses if a more disorderly fallout results.

China will again top the economic growth charts this year with growth of 8.4 percent, although that is only a little over the 8 percent mark economists deem necessary to create enough jobs to satisfy the country's fast-growing population.

India's economy will not be far behind, expanding 7.0 percent in the 2012 fiscal year, although that would still be its worst showing in two years thanks to tight monetary policy and political deadlock.

Brazil's fervent domestic demand and credit growth should propel the economy to growth of around 3.3 percent in 2012, and 4.5 percent in 2013.

DIFFICULT TIMES

This year looks certain to be difficult for the rich developed economies. The world's largest, the United States, should grow around 2.2 percent in 2012.

While fairly modest by historical standards and compared to its emerging peers, that would be vastly better than the 0.3 percent contraction expected for the euro zone economy.

The immediate risk to Europe's economy would be a disorderly sovereign debt default from Greece that would hammer the European financial system. Athens is bargaining with its private creditors on a bond swap deal needed before it can repay 14.5 billion euros ($18.5 billion) of bonds falling due in March.

The seeming inability of euro zone policymakers to get on top of the region's sovereign debt crisis is threatening to exact a toll on economic growth well beyond its peripheral economies, said Mark Cliffe, chief economist of ING Group.

Germany will probably be the only major economy in Europe to rise above stagnation this year, although not by much - economists expect its economy to expand by 0.5 percent in 2012.

Even Japan, mired in deflation and struggling to overcome the economic shock of the earthquake and tsunami last March, will easily outstrip European economies with growth of around 1.8 percent in its fiscal year 2012-13.

That is the lowest forecast since the aftermath of last year's natural disasters, however, underscoring how over-optimistic some commentators were in expecting reconstruction to fuel a rapid expansion.

Backed by a mining boom, Australia's resource rich economy should lead the developed world in terms of growth, with a hearty 3.4 percent expansion this year.

The mining investment boom is largely 'baked in' and is expected to contribute two-thirds of GDP growth in 2012, said Paul Bloxham, chief economist at HSBC Bank Australia.

(Reporting by Andy Bruce; Polling led by Shaloo Shrivastava in Bangalore and Reuters bureaux around the globe; Editing by Ross Finley and Catherine Evans)

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