A finance think tank agrees with the federal government that delivering a surplus next year would further boost the Australian economy, already heading into relative growth despite the lingering global difficulties.

"A well-constructed fiscal consolidation would place downward pressure on interest rates and the exchange rate ... spending cuts also lower the risk premium on public debt and reload the fiscal cannon if future fiscal stimulus is required," a new report by economic consultancy firm Macroeconomics said on Friday.

The report, however, also warned that Federal Treasurer Wayne Swan may not be able to achieve his surplus goal at all when he presents the national budget on May 8.

In an interview with Business Day, Macroeconomics chief Stephen Anthony insisted that Mr Swan will have to deal with revenue shortfalls that run as high as $6 billion, no thanks to the economic difficulties that non-mining firms have been encountering.

In its report titled 'Commonwealth & State Government 2012/13 Budget Bulletin', Macroeconomics cited the declining terms of trade, lower capital gains receipts, shrinking company tax receipts and mining investment depreciation as major factors that pushed down both federal and state revenues.

Eventually, the Treasurer will find himself absorbing a deficit of up to $7.8 billion for the financial year 2012-2013 instead of the thin $1.5 billion surplus that Prime Minister Julia Gillard said will would be met in the upcoming budget.

For the surplus to become a reality, the federal government will have to cut deep on its planned expenditures, Mr Anthony said, by at least $10 billion.

And in order to gain structural surplus, the cuts will have to reach $15 billion, the Macroeconomics chief said.

"Along with declining terms of trade, a weaker than expected economy and mining industry depreciation expenses in place of taxable profits, it has put a spanner in the works," Mr Anthony explained.

Macroeconomics forecasted on its report a deficit of more than $40 billion in the current financial year, a trend that will be sustained through fiscal year 2015.

For the two financial years after 2012-2013, Macroeconomics projected that the deficit would reach $7.8 billion and $6.2 billion respectively, erasing the surpluses that the Labor-led government said will grace the Australian economy over the next few years.

The country's net debt levels, the report said, will also surge along with the projected deficits, possibly soaring to 9.4 percent of the gross domestic product (GDP) in 2012-2013 and 9.7 percent by 2015-2016.

To stave off the likelihood of runaway deficits, Macroeconomics urged the government to impose spending cuts that would be felt by the middle and upper classes, "spreading the pain of adjustment as thinly as possible and imposing the largest burden on those likely to benefit from an upswing in the business cycle."

According to News.com.au, a likely casualty on the proposed revenue-raising scheme by the government is the fuel rebate being enjoyed by mining firms, the scrapping of which, based on a study by the Australian Conservation Foundation (ACF), would deliver savings of up to $2 billion to the federal coffers.

A survey conducted by ACF in mid-April also showed that eight out of 10 Australians would approve the withholding of the rebate while expecting that the money should be used up instead on education and health programs of the government.