Feb 17 (Reuters) - Australian shares started the week lower on Monday, led down by heavyweight banking and gold stocks, as investors brace for the domestic central bank's interest rate decision this week.

The S&P/ASX 200 index .AXJO dropped 0.5% to 8,510.1, as of 1208 GMT. The benchmark had closed 0.4% higher on Friday, after hitting a record high of 8,615.20.

Financials .AXFJ dropped 1.6%, on track for their third straight session of losses, after all of the "Big Four" lenders tanked. Westpac WBC.AX, down 5.9%, fell most since August 5.

Westpac posted a rise in its first-quarter net profit but based on the bank's average quarterly performance in the second half of 2024, profit was down 9%.

Top lender Commonwealth Bank of Australia CBA.AX shed 2%, while National Australia Bank NAB.AX and ANZ ANZ.AX tracked the subdued sentiment, losing more than 2% each.

The Reserve Bank of Australia will announce its cash-rate decision on Tuesday. Most market participants now expect the RBA to proceed with a quarter-point rate cut. Over 90% of 43 economists polled by Reuters are predicting a 25 basis point cut. 0#AUDIRPR

Gold stocks .AXGD dropped 3.3% after an eight-session rally, as bullion fell on Friday amid profit-taking. GOL/

Northern Star Resources NST.AX led the declines, down 3.9%, while Evolution Mining EVN.AX fell 4.3%.

Energy stocks .AXEJ shed 1.5%, as crude oil prices fell on prospects of a peace deal between Russia and Ukraine, easing tensions regarding global supply disruptions. O/R

Australia's no.1 independent oil and gas producer Woodside Energy WDS.AX dragged the sub-index, shedding 3.2%.

In New Zealand, the benchmark S&P/NZX 50 index .NZ50 rose 0.3% to 13,027.81.

(Reporting by Nichiket Sunil in Bengaluru; Editing by Rashmi Aich)

((Nichiket.Sunil@thomsonreuters.com;))

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