Uncertainty over the human and economic damage inflicted by Japan's earthquake, tsunami and nuclear crisis weighed on Asia stocks on Wednesday, and the euro eased ahead of a parliamentary vote in Portugal that could see the government fall.

Major European share markets were expected to open down around 0.4 percent, according to financial bookmakers in London, while S&P 500 futures fell 0.3 percent, pointing to a weaker start on Wall Street. <.EU>

Oil was steady, after gaining on Tuesday as violence in Libya and unrest in Yemen fueled worries of supply disruptions. Turmoil in North Africa and the Middle East also supported safe-haven demand for gold.

Japan's Nikkei <.N225> fell 1.7 percent as investors took profits from a two-session bounce. Japanese stocks remain around 8 percent below their close on March 11, the day northeast Japan was struck by a 9.0 magnitude earthquake and 10-meter tsunami.

The disaster left more than 23,000 people dead or missing, crippled a nuclear power plant that has been leaking radiation and hit production at major companies such as Sony Corp <6758.T> and Toyota Motor <7203.T>.

A Japanese government report estimated the material damage from the disaster at around $200-$300 billion and said planned power outages would have a significant additional impact.

It's not that the market is ignoring fundamentals, said Takashi Hiroki, chief strategist at Monex Inc. We just simply don't know them yet, as many companies are still gathering information about damage sustained during the disasters.

Underlining the continuing risks, the United States became the first country to block food imports from parts of Japan due to radiation fears.

CAUTION PREVAILS

MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> was flat, weighed down by the Japan crisis and following falls on Wall Street, where the Dow Jones industrial average <.DJI> lost 0.2 percent and the S&P 500 <.SPX> fell 0.4 percent. <.N>

It's fairly evident that while we have had added strength in our market, there is still caution out there, with the view that markets are not going to race up in any great hurry, said Jamie Spiteri, senior dealer at Shaw Stockbroking in Australia.

Nervousness and volatility in the stock market supported Japanese government bonds, with benchmark 10-year futures rising 0.33 point to 139.73, while the 10-year yield fell 3 basis points to 1.215 percent.

The incident is likely to slow Japan's economic growth, so markets are expected to factor this in, said Akito Fukunaga, chief fixed-income strategist at RBS Securities.

I think the influence of the economic slowdown surpasses worries over Japan's fiscal position in the JGB markets.

PORTUGAL CRISIS

Portugal's parliament was due to vote on the minority Socialist government's latest austerity measures on Wednesday, with Prime Minister Jose Socrates threatening to resign if the opposition rejects the proposals.

If Prime Minister Socrates steps down, Portugal will likely ask the European Union and the IMF for help, which is likely to trigger a bit of euro selling, said Junya Tanase, chief strategist at JPMorgan Chase Bank in Tokyo.

The euro traded around $1.4165, off a four-month high near $1.4250 reached on Tuesday.

Also weighing on the euro were rumors that Allied Irish Banks , which has been effectively nationalized, was planning to miss a coupon payment, driving the premium that investors demand to hold Irish 2-year bonds to a euro-era high.

AIB said in a statement it would pay the coupon due on Wednesday as scheduled.

The yen remained little moved over the past 24 hours, hugging a tight range close to 81 per dollar. Traders were wary the Bank of Japan might step in again if the dollar fell below 80.50, following Friday's rare market intervention by leading central banks to curb the currency's strength.

Last week, expectations the cost of quake reconstruction would prompt insurance firms and others in Japan -- a big net creditor to the rest of the world -- to repatriate yen drove the Japanese currency to a record 76.25 per dollar before the Group of Seven launched the first coordinated intervention since 2000.

Oil edged down a touch, after gaining on Tuesday as fighting in producer Libya and unrest in Yemen, which neighbors top producer Saudi Arabia, fueled worries of supply disruptions. Brent crude eased 0.3 percent to $115.44.

The market is still very vulnerable to further disruptions to supply, said Tetsu Emori, a Tokyo-based commodities fund manager at Astmax Investments. People are quite nervous about the current turmoil spreading to Saudi Arabia.

Spot gold was steady around $1,427.35 an ounce.

(Editing by Jeremy Laurence)

Down Portugal