* Index rises for the second day
* Index on track to post another weekly gain
* 172 shares up, 23 down and 5 unchanged (Adds analysis, quotes, stocks on the move)
By Pauline Askin and Charlotte Greenfield
SYDNEY/WELLINGTON, Sept 17 (Reuters) - Australian shares rose 1.5 percent on Thursday for a second straight day of gains as all sectors rallied ahead of the U.S. Fed's interest rate decision later in the day.
Banks and miners were among the clear winners with the "Big Four" lenders rising more than 2 percent in early trade. A jump in oil prices pushed energy stocks higher.
The S&P/ASX 200 index .AXJO added 73.83 points to 5,172.7 by 0215 GMT. The index closed 1.6 percent higher on Wednesday, and is on track to post a second straight weekly gain.
Analysts said the market could claw back some of the day's gain as the near-month futures contract expires on Thursday and could add some volatility.
Asian stocks hit a three-week high on Thursday after a jump in oil prices lifted Wall Street, with many investors taking last-minute positions ahead of the Fed's policy decision.
Major banks Westpac WBC.AX , ANZ ANZ.AX and NAB NAB.AX each gained more than 2 percent while Commonwealth Bank CBA.AX was up 1.34 percent.
Mining giant BHP Billiton (LONDON:BLT) BHP.AX jumped 2.84 percent while Rio Tinto (LONDON:RIO) RIO.AX rose 1.93 percent.
Newcrest Mining NCM.AX rose as much as 5.9 percent after a rise in gold prices.
Energy stocks forged higher with Woodside Petroleum WPL.AX and Santos Ltd STO.AX both rising by more than 3 percent.
New Zealand's benchmark NZX50 share index .NZ50 rose 0.66 percent or 37.87 points to 5,705.840 on Thursday, supported by gains in the material and consumer sectors.
Dual-listed shares rose, tracking strong gains in the Australian sharemarket, with auction website Trade Me TME.NZ TME.AX up 4.46 percent, Fletcher Building FBU.NZ FBU.AX up 3.03 percent, and Sky Network Television SKT.NZ SKT.AX up 2.08 percent.
Meridian Energy MEL.NZ fell 1.35 percent, reversing gains from a rally the previous session. Z Energy edged down 0.3 percent, extending losses that began early this week when a rival asked regulators for Z Energy ZEL.NZ to sell assets as a condition of a planned deal to take over Chevron (NYSE:CVX) New Zealand.