May 20 (Reuters) - Australian shares climbed on Tuesday, driven by broad-based gains in mining stocks and banks, as investors awaited the Reserve Bank of Australia's policy decision later in the day.

The S&P/ASX 200 index .AXJO was up 0.7% at 8,356.7, as of 0033 GMT. The benchmark closed 0.6% lower on Monday.

The Reserve Bank of Australia is set to deliver its closely watched interest rate decision later in the day. Economists surveyed by Reuters reckon the RBA will cut by 25 basis points, and market pricing indicates a 99.8% probability. 0#AUDIRPR

The financials sub-index .AXFJ gained 1.2%, with shares of National Australia Bank NAB.AX and Westpac WBC.AX up 1.7% and 1.6%, respectively.

ANZ ANZ.AX and Commonwealth Bank of Australia CBA.AX advanced 1.2% and 1.1%, respectively.

The mining sector .AXMM rose 0.6%, with shares of major miners BHP BHP.AX and Fortescue FMG.AX gaining 0.5% and 0.8%, respectively.

Rio Tinto RIO.AX said Chile's state-owned copper producer Codelco on Monday has selected the global mining giant as a partner for its Maricunga lithium project. Shares of Rio were up 0.7%.

Shares of gold miners St Barbara SBM.AX and Northern Star Resources NST.AX were up 1.6% and 0.6%, respectively.

Energy stocks .AXEJ rose 0.6%, supported by Woodside Energy WDS.AX and Santos STO.AX, up 0.2% and 0.8% respectively, as oil prices climbed on concerns over a potential breakdown in U.S.-Iran nuclear talks, dimming prospects for increased Iranian oil supply. O/R

In company news, Australia-based enterprise software firm TechnologyOne TNE.AX surged 10%, becoming the benchmark's top gainer after reporting a 31% increase in first-half results and raising its fiscal 2025 profit outlook to 13% to 17%.

New Zealand's benchmark S&P/NZX 50 index .NZ50 rose 0.6% to 12,702.42.

Around the globe, Japan's Nikkei .N225 was up 0.85%. The U.S. S&P 500 index .SPX and the Nasdaq .IXIC were mostly steady on Monday.

(Reporting by Roshan Thomas in Bengaluru; Editing by Sherry Jacob-Phillips)

((Roshan.Thomas@thomsonreuters.com))

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