Asian stock markets struggled on Wednesday as weaker U.S. data damped down recent optimism that the world's largest economy may escape the gloom from the euro zone debt crisis, while Chinese manufacturing surveys failed to break the cautious mood.

Financial spreadbetters expected Britain's FTSE 100 <.FTSE>, Germany's DAX <.GDAXI> and France's CAC-40 <.FCHI> to open up around 0.4-0.6 percent.

MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> fell 0.3 percent in a volatile session in which the indexed yo-yoed between positive and negative territory.

Japan's Nikkei average <.N225> bucked the regional trend to close up 0.1 percent, as fund managers took the view that Japanese stocks remain undervalued. <.T>

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Greek/Portuguese yields: http://link.reuters.com/syw36s

Asset returns in 2012: http://link.reuters.com/nyw85s South Korean exports: http://link.reuters.com/ryz36s

Asia debt issuance: http://link.reuters.com/kux97r

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Data from China failed to give markets a decisive lead.

Shares strengthened after the official Purchasing Managers' Index showed the manufacturing sector expanded modestly in January, with the index reading inching up to 50.5 from 50.3 in December, above a 49.5 reading forecast.

But the rise petered out after the release of a separate private sector survey later. The HSBC final PMI stood at 48.8 in January, a reading signalling contraction albeit at the slowest pace in three months.

Oil and copper firmed, however, with Brent crude rising above $111 a barrel and London copper trading steady.

The official January China PMI numbers, on their own, look better-than-expected, but I think investors are taking this with a pinch of salt, said Edward Huang, an equity strategist at Haitong Securities International.

The data hinted the world's second-biggest economy may avoid a hard landing and a downturn in manufacturing may be bottoming out. A reading below expectations could have fuelled concerns that policy makers were not taking sufficient steps to spur growth and stoked worries about weakening demand.

The data merely highlights lacklustre growth, as Asia is the main exporter to Europe, and it will only become clearer that the European debt woes are having an impact on the real economy around the world, said Takao Hattori, senior investment strategist at Mitsubishi UFJ Morgan Stanley Securities in Tokyo.

The probability of the euro zone debt problems turning into a global financial crisis has receded considerably and the risk of global growth grinding to a halt is low, but that doesn't change the main scenario for an economic slowdown generally.

MORE PMI

Earlier, South Korea said its exports unexpectedly fell in January while exports to the European Union for the January 1-20 period nearly halved from a year ago.

Investors were on their guard ahead of more manufacturing surveys due later this session, including the euro zone and the Institute for Supply Management index from the United States.

The euro zone flash inflation for January and U.S. January employment data from ADP are also due.

The reports were likely to show many economies are seeing a sluggish start in 2012 amid slowing demand, putting central banks around the world under pressure to keep an accommodative policy to support growth.

Inflation is likely to ease further in the months ahead, giving central banks room to cut. With cuts priced in, demand-supply dynamics are more useful in gauging direction, said Standard Chartered in a research note.

BONDS FIRM

The dollar matched a three-month low of 76.14 yen touched on Tuesday. The euro slipped 0.1 percent to $1.3068 on a lack of concrete progress in Greece's debt restructuring talks with private bond holders.

Athens struggled to convince foreign lenders it could bridge a funding shortfall with reforms. A senior Greek banker said the crucial debt swap deal to avoid a default was largely in place, but a final accord hinged on Athens showing its determination to pursue tough measures.

Portugal, which has come under fire from markets recently, said it has no intention of asking for more funding or extending its bailout. Lisbon has a far lighter calendar than Athens with just one payment due this year.

Portuguese government bond yields took a respite from a recent surge, while Italy and Spain, the other highly indebted euro zone countries only recently at the centre of market jitters over their refinancing, saw their debt yields move further away from peaks deemed unsustainable for the economy.

The 30-year Japanese government bond yield dropped to a four-month low of 1.890 percent on Wednesday.

With credit risks still simmering, government bonds of industrialised countries will likely continue to attract investors, Hattori said.

Asian credit markets steadied, with spreads on the iTraxx Asia ex-Japan investment grade index narrowing by 4 basis points.

(Additional reporting by Clement Tan in Hong Kong; Editing by Alex Richardson)