(Reuters) - Asian shares eased Tuesday ahead of a key German ruling on the euro zone's bailout funds and the U.S. Federal Reserve's policy decision, repositioning from last week's rally spurred by heightened speculation for more stimulus globally.

MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> ticked down 0.2 percent, with Australian shares <.AXJO> down 0.1 percent and South Korean shares <.KS11> down 0.4 percent.

Japan's Nikkei average <.N225> opened down 0.7 percent..T

Global shares slipped and the euro fell as investors took profits from last week's rally after the European Central Bank outlined its bond-buying scheme designed to cap the rise in the borrowing cost of highly indebted euro zone states such as Spain.

"Looking at the U.S. and European markets, investor sentiment does not seem to be that strong." said Masayuki Doshida, senior market strategist at Rakuten Securities.

"They were selling following China's slowdown, but they were curbed only by hopes ahead of key events," he said, referring to Germany's constitutional court ruling on the euro zone's bailout fund on Wednesday and the Fed's two-day policy meeting ending on Thursday.

Following Friday's disappointing U.S. jobs data, markets now believe the Fed will take some type of further monetary easing step this week to help underpin the fragile U.S. recovery.

But views remain mixed over the specifics. Some see a powerful move such as a third round of bond buying known as quantitative easing while others expect other options such as extending its commitment to keep interest rates near zero beyond the current period through late 2014 into 2015.

Reflecting growing investor jitters, the CBOE Volatility index <.VIX>, which measures expected volatility in the Standard & Poor's 500 index <.SPX> over the next 30 days, closed up 13.21 percent on Monday for its largest daily increase in seven weeks.

The euro steadied around $1.2764, off Monday's low of $1.27553 but slipping from Friday's four-month peak of $1.2815.

"Profit taking continues ahead of the Fed decision on Thursday and Wednesday's German constitutional court on ESM participation. This seems tactical in nature, but nervousness is creeping," said Sebastien Galy, a strategist at Societe General.

U.S. crude eased 0.3 percent to $96.26 a barrel while Brent inched down 0.2 percent at $114.64 a barrel.

Spot gold was up 0.2 percent at $1,727.57 an ounce, below a six-month high of $1,741.30 touched on Friday.

With the euro zone debt crisis severely undermining economic activities in Europe and dealing a blow to the world's growth engine China, which counts Europe as its key export market, the ripple effect is spreading to the rest of Asia.

South Korea announced an incremental stimulus package on Monday to nurse its export-driven economy through prolonged hard times, a move many Asian governments are expected to follow as Europe slides towards recession and the United States struggles to grow.

Europe continues to muddle through its crisis management, with Greece admitting on Monday it was having trouble convincing its foreign lenders to accept its two-year austerity plan which is essential to revive the aid payments the country needs in order to avoid bankruptcy.

Spain, suffering from its huge sovereign and provincial government debts, has already received aid of up to 100 billion euros ($127.86 billion) from the euro zone to help it shore up its ailing banks.

Madrid has made it clear it could seek a sovereign rescue once euro zone partners and the ECB provide details on conditions attached, and will likely hold discussions at the September 14-15 meetings of euro zone and EU finance ministers.

With the ECB announcing its bond-buying scheme Spanish 10-year government bond yields have stayed below 6 percent, down sharply from the 7 percent level hit in late July.