(Reuters) - Asian shares fell Wednesday morning after recent rally, but the euro held near a seven-week high on hopes the European Central Bank will act to rein in surging euro zone borrowing costs and policymakers will find ways to keep Greece on lifelines.

Top global miner BHP Billiton may put three mega projects on hold on Wednesday when it is expected to report its first annual profit fall in three years due to rising costs and falling commodity prices.

BHP's woes will wrap up a torrid earnings season for the world's biggest miners, all battered by weaker prices for iron ore, copper, coal, nickel and aluminum as economic growth in big-buyer China slows to its weakest pace in a decade.

MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> was down 0.3 percent while Japan's Nikkei stock average <.N225> fell 0.4 percent. .T

Data on Wednesday showed Japan's exports fell 8.1 percent in July from a year earlier, boding ill for the fragile economy heavily dependent on overseas demand.

Asian credit markets were steady, with the spread on the iTraxx Asia ex-Japan investment-grade index barely changed and pinned near its tightest level in five months.

Asian equities are not yet overbought, judging from the amount of net foreign buying, which stood at $8.1 billion so far in August, Credit Suisse said in a research note. They define markets to be overbought when net foreign buying on a rolling 12-month basis is 1 percent of market capitalization or more and net foreign buying over two months is 0.6 percent or more.

"On this definition, we are not yet overbought, as net foreign buying over the past 12 months is 0.6 percent of market cap, and over the past two months is 0.26 percent," it said.

Speculation that the ECB will take a decisive step to cut borrowing costs in Spain and Italy to help reduce their high public debts gained further momentum with an article in London's Daily Telegraph, which said the ECB was examining plans to put a hard cap on Spanish and Italian yields.

A similar report on the ECB's bond-buying scheme in German media was on Monday denied by the bank, which also repeated its stance over the latest British report.

Meanwhile, German Chancellor Angela Merkel has voiced support for the ECB's crisis-fighting strategy last week.

"The market rallied on growing convictions that Germany stands ready to do more to keep the eurozone united. Merkel's government seems more willing to ease the official debt burden on Greece, as long as the basic elements of the second bailout program remain," Barclays Capital said in a research note.

The euro traded at $1.2470, not far from $1.2488 hit on Tuesday, its highest since July 5.

The dollar was down 0.1 percent against the yen at 79.24 yen, off a five-week high at 79.66 yen hit on Monday. The dollar index .DXY measured against key currencies hovered near its seven-week low touched the previous day.

U.S. stocks fell on Tuesday as investors took profits after driving the Standard & Poor's 500 index.SPX to a four-year high, while European shares rose and yields in Spain and Italy fell further. Spain's 10-year debt yields have shed about 8 percent this month.

A rise in the CBOE Volatility Index .VIX, a gauge of Wall Street's risk sensitivity, U.S. Treasury yields capped at recent highs and many assets failing to top the upside of their ranges suggested, however, investor were not entirely convinced yet of a breakthrough in the three-year euro zonedebt crisis.

Greek Prime Minister Antonis Samaras is holding bilateral talks with leaders of France, Germany and the Eurogroup this week to seek concessions for its austerity-to-bailout swap. His meeting with Merkel is set for Friday.

Oil inched higher, with Brent up 0.2 percent to $114.81 a barrel and U.S. crude up 0.1 percent at $96.90.

Spot gold eased to $1,637.21 an ounce after hitting a 3-1/2 month high of $1,641.20 on Tuesday, while platinum also retreated from its highest since early May at $1,508.25 hit the previous session.

The worst U.S. drought in half a century hoisted soybeans on Tuesday to another peak, and corn up nearly 2 percent.