(Adds share moves, analyst comments)
SYDNEY May 12 (Reuters) - Australian shares fell 0.3 percent on Monday morning, dragged by big miners on soft iron ore prices and profit-taking in banks, as investors tread cautiously ahead of the coalition government's first federal budget.
The conservative coalition government of Prime Minister Tony Abbott will hand down its first budget on Tuesday, with big spending cuts forecast, along with tax hikes and spending on infrastructure.
"The obvious thing is what the budget will dictate... it's very quiet pending the release and what is contained within the budget to what the next move will be with our market," said Tony Russell, senior equities adviser at RBS Morgans.
The S&P/ASX 200 index lost 15.4 points to 5,445.4 by 0119 GMT. The benchmark dipped 15.9 points to 5,460.8 on Friday.
Bluechip miners BHP Billiton Ltd and Rio Tinto Ltd declined 1.2 percent and 1.0 percent, respectively, after spot iron ore fell to its cheapest since September 2012 on Friday.
Miners have been under pressure as rising supply of iron ore and slack demand for steel in top consumer China threatened to pull prices below $100 a tonne.
Most big banks gave up earlier gains and slipped into the red. Commonwealth Bank of Australia fell 0.1 percent, and Westpac Banking Corp declined 0.2 percent. National Australia Bank bucked the trend and edged up 0.1 percent.
"Keeping in mind those banks have had an excellent run over the last 12 to 18 months, we will probably see a little bit of profit-taking coming out those as well," Russell said.
Consumer stocks also pulled back, with supermarket chain Woolworth Ltd skidding 0.4 percent and Coles-owner Wesfarmers Ltd slipping 0.2 percent.
Leighton Holdings Ltd lost 2.1 percent after the company said the head of its Thiess subsidiary in India had been arrested by police and the main client for its Pakri Barwadih coal mine was attempting to terminate its contract.
Oil and gas producer Dart Energy surged 28.0 percent after Britain's IGas last week agreed to take over the company in an all-share deal valuing the company at 117 million pounds ($198.35 million).
Explosives producer Incitec Pivot Ltd rose 0.9 percent on news its first-half net profit rose 7 percent to A$115.7 million.
Kimberley Diamonds Ltd plunged 38.5 percent after it said it failed to secure price increase for supply of fancy yellow diamonds with a unit of Tiffany & Co.
New Zealand's benchmark NZX 50 index inched up 0.1 percent to 5,158.3.
(Reporting by Maggie Lu Yueyang; Editing by Shri Navaratnam)