March 18 (Reuters) - Australian shares inched lower on Monday, dragged down by losses in heavyweight mining and financials stocks, as investors braced for a central bank policy decision due on Tuesday.

The S&P/ASX 200 index had declined 0.3% to 7,647.0 by 2351 GMT, heading for a third consecutive session of falls.

The Reserve Bank of Australia (RBA) is expected to hold its key interest rate at 4.35% for a third straight meeting on Tuesday and at least until end-September, according to a Reuters poll of economists.

While financial markets have priced in rate cuts for most other major central banks starting around June, the RBA is a notable outlier with no such mid-year pricing.

Miners fell 0.3% after iron ore prices tanked on Friday as concerns grew about demand from China with increasing prospects of steel production cuts in the country.

BHP Group and Fortescue declined 0.2% and 1.6%, respectively, while Rio Tinto edged 0.2% higher.

Mineral Resources rose as much as 0.9% after the company said it would develop a lithium processing hub in Western Australia.

Financials eased 0.1%, down for a third consecutive session. Commonwealth Bank of Australia, the country's biggest lender, rose 0.4%.

Energy stocks dropped 0.5% after oil prices closed lower on Friday. Woodside Energy and Santos were down 0.9% and 0.2% respectively.

Tech stocks fell 0.7% and were on track for a third session of declines, after their Wall Street counterparts settled lower on Friday.

New Zealand's benchmark S&P/NZX 50 index fell 0.3%, or 40.58 points, to 11,726.4.

Critical data points like fourth-quarter current account balance and gross domestic product (GDP) numbers are due this week.

The current account deficit was expected to narrow, while the GDP growth was estimated to be flat, according to Westpac analysts.

(Reporting by Sneha Kumar in Bengaluru; Editing by Subhranshu Sahu)