Wall Street was set for a higher open on Wednesday as new signs of growth in China and Australia eased concerns about the global economy's health and investors shrugged off an unexpected cut in U.S. private sector payrolls.

China's manufacturing economy staged a moderate rebound in August, while Australia's economy grew at its fastest pace in three years on a boost in household spending.

That helps when you get positive news in here out of the emerging markets, the leaders. So that's always good, said Frank Lesh, a futures analyst and broker at FuturePath Trading LLC in Chicago.

The Chinese manufacturing data helped boost metals prices, lifting copper to its highest level in more than four months. Shares of aluminum producer Alcoa Inc gained 1.6 percent to $10.38, and Freeport McMoRan Copper & Gold Inc advanced 2.5 percent to $73.80 in premarket trade.

Futures briefly pared gains after a report from ADP Employer Services showed U.S. private firms unexpectedly cut 10,000 jobs in August compared with a revised gain of 37,000 in July.

There is always that thought that it doesn't take the whole picture in, and the correlation (with Friday's employment report) isn't always strong. So it seems like today we'll take a little bit of a wait-and-see, added Lesh.

S&P 500 futures rose 12.9 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures climbed 103 points, and Nasdaq 100 futures gained 25.5 points.

The Institute for Supply Management releases its August manufacturing index at 10 a.m. EDT. Economists look for a reading of 53.0 versus 55.5 in July.

Also at 10 a.m., the Commerce Department reports on July construction spending. Economists forecast a fall of 0.5 percent, compared with an 0.1 percent rise in the prior month.

Burger King Holdings Inc , the No. 2 U.S. hamburger chain, may put itself up for sale and has already talked with potential buyers, a source said.

Its shares jumped 17.6 percent to $19.35 premarket.

Apple Inc is expected to show off a snazzier line of iPods later Wednesday and may also unveil plans to reinvigorate its long-neglected TV line. Shares rose 1.4 percent to $246.41 premarket.

H.J. Heinz Co posted an increase in quarterly gross margin as higher pricing in emerging markets helped offset North American promotions.

Genzyme Corp Chief Executive Henri Termeer told Reuters he is willing to sell the company he built up over 25 years, but not for $69 a share.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)