Shares of Australia's "Big Four" banks pulled its benchmark...

Shares of Australia's "Big Four" banks pulled its benchmark stock index lower on Friday, though losses were capped by caution ahead of speeches by the heads of the U.S. and European central banks later in the day.

Investors will be closely parsing speeches by Federal Reserve Chair Janet Yellen and European Central Bank President Mario Draghi at the annual central bankers' retreat in Jackson Hole, Wyoming for any clues on the path of monetary policy.[MKTS/GLOB]

The S&P/ASX 200 index (xjo) was down 0.3 percent, or 14.78 points, at 5,729.80 by 0212 GMT.

"It's a cautious market and to a large extent, reflects people watching and waiting for what comes out of the Jackson Hole symposium." said Tony Farnham, an economist at Patersons Securities.

"People are going to be watching closely just in case Yellen says something about the wind-back in the Fed’s balance sheet, or perhaps the timing of interest rate hikes."

Yellen and Draghi are scheduled to speak at 1400 GMT and 1900 GMT, respectively.

Financial stocks were the biggest drag on Australia's main index, with dominant lenders Westpac (WBC), Commonwealth Bank of Australia(CBA), National Australia Bank (NAB) and Australia and New Zealand Banking Group (ANZ) losing 0.7 percent to 1.3 percent.

The Aussie mining index .AXMM slid 0.3 percent, with mining giants BHP Billiton (BHP) and Rio Tinto Ltd (RIO) losing 0.5 percent and 0.6 percent, respectively.

Real estate stocks also recoiled, with Scentre Group (SCG) falling as much as 3.1 percent to a near two-year low.

"Stocks like BHP in the material sector have rallied off pretty good results. Inevitably, when there’s a good run up, people want to take a bit of profit" Farnham added.

Bucking the trend, energy stocks gained with the Australian energy index .AXEJ rising 1.1 percent.

Shares of natural gas company Santos Ltd (STO) climbed 4.6 percent to their highest in over three months after it reported half-year net profit that beat analysts' estimates on Thursday.

Oil prices were volatile early on Friday as the market tried to gauge the potential impact of Hurricane Harvey heading for the coast of Texas.[O/R]

Oil and gas explorer Woodside Petroleum (WPL) rose nearly 1 percent.

New Zealand's benchmark S&P/NZX 50 index (nz50) rose 0.1 percent, or 7.73 points, to 7,876.14 by 0140 GMT.

Consumer staples led the gains while healthcare stocks were a drag on the index.

Dairy firm a2 Milk Company (ATM) extended record gains for the third straight session, climbing 3.8 percent after it reported upbeat annual earnings on Wednesday.

Fisher & Paykel Healthcare (FPH) was the biggest drag on the index, falling 1.5 percent.