Australia's mining and energy investment boom continues to stun observers with data today showing an acceleration in plans to expand capacity to meet Asia's insatiable appetite for iron ore, coal and liquefied natural gas.

While only an early estimate, the data from the Australian Bureau of Statistics points to a planned 32 per cent increase in business investment in the year ending June 30, 2012 from a year earlier, according to economists' analysis.

Expansion plans among miners are the most aggressive, with economists expecting $100 billion to be invested in 2011-12. This would be around 95 per cent higher than the prior year.

International energy companies are ploughing billions of dollars into natural gas to capitalise on what they expect will be a surge in demand for cleaner-burning fuels. Australia's stable political environment, substantial gas reserves and proximity to fast-growing Asian economies make it an attractive place to invest, particularly with US gas prices low in the wake of a flood of domestic gas supply. 

“It indicates that the resources boom will be much larger, and extend for longer, than previous such experiences,” said Stephen Walters, chief economist at JPMorgan.

The stunning numbers surrounding the outlook for mining investment are timely as the impact of economic stimulus, put in place by the Australian government after the global financial crisis, is now waning.

Economists said the private sector is now well placed to sit in the driver's seat of the economy, replacing public spending.

The data emerged a day after Reserve Bank of Australia Governor Glenn Stevens said the country was experiencing the biggest terms of trade boom since the start of the 1900s, as he urged that the revenue windfall be saved. 

Earlier today, the head of macro-economic forecasting at Australia's Treasury, David Gruen, said China and India's expansions are still in their early stages.

“China and India have the potential for strong catch-up growth for at least a few more decades,” Mr Gruen said.

The strength of the investment surge has stirred talk of interest rate increases in Australia earlier rather than later, with attention focused on a central bank policy meeting in May.

“A tightening bias by the RBA is understandable given the strain this will put on an economy that is already operating somewhere close to capacity,” said Michael Turner, economist at RBC capital Markets.