Wayne Swan says the Government is "determined" to deliver a budget surplus next financial year despite taking a $130 billion hit from the global financial crisis.

The Federal Treasurer has revealed a deficit of nearly $48 billion for the 2010-11 financial year.

Final budget outcome figures from last financial year released today show tax receipts came in $1.7 billion below the prediction of this year's budget, which will make the forecast surplus hard to achieve.

The Government also blames the flooding and cyclone natural disasters early this year for pruning GDP growth by 0.75 per cent.

Mr Swan warned the current volatility in global markets will "weigh heavily" on budget revenues adding to the pressures of the global financial crisis.

"We'll have softer revenues going forward as a consequence of the global instability," he told journalists in Canberra.

"All of that will make it more difficult to reach surplus in 2012-13 but we are absolutely determined to do that."

Documents released by Treasury today say despite weakness in company tax revenue, the budget is expected to show a surplus in 2012-13 in line with this year's budget prediction.

In May, the Government forecast a budget surplus of $3.5 billion for 2012/13 after four consecutive deficits.

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Tax from individuals actually rose, however, driven by stronger-than-expected receipts from capital gains taxes.

Net debt is $84.6 billion dollars or 6.1 per cent of GDP - far lower than most other advanced economies.

Mr Swan said the high Australian dollar is hitting the nation's economy but despite the pressures, Australia's budget position "remains amongst the strongest in the developed world".

"These figures demonstrate that the budget is in good shape particularly with low debt and that is one of the reasons Australians can be so confident that our economic fundamentals are strong," he said.

He said it is too early to forecast what Australia will do if the world economy tanks.

"We will deal with the cards when they're dealt. These events have got some way to play out," he said.

"We have shown in the past that if conditions change dramatically we have the ability, capacity and the proven record to deal with those circumstances."

And Mr Swan played down the importance of next week's tax forum between the Government, unions and business, saying no hard decisions on tax policy will be made.

"We're going to have a yarn with a couple of hundred people about tax. That's a good thing. It's a healthy thing," he said.

"But a substantial reform to the tax system is not something that is made in one or two days of discussion.

"What they are made in is pretty healthy discussion and debate, then considered government policy over time - and that's how we are going to proceed."

Acting shadow treasurer Andrew Robb has accused Mr Swan of trying to hide the figures from the public by releasing them in the run-up to the grand finals weekend.

"If I was Wayne Swan I would be deeply embarrassed and I would try to bury these numbers in the midst of the grand finals," Mr Robb told reporters in Melbourne.

"These are the two worst consecutive budget deficits in the nation's history.

"We've got a situation where this government has never delivered a surplus, and I don't think it will ever deliver a surplus."

Mr Robb warned that Australia would have a "a real problem" and could face "endemic budget deficits" if commodity prices fall.

He said Australia's debt would take many years to pay off "whoever is in government".