Federal Treasurer Wayne Swan remains upbeat that the Labor-led government will deliver a budget surplus in 2013 despite indications that tax collections for the current financial year would fall short of expectations.

But he admitted that the task would be a great challenge for the national government to do so, insisting too that it's not an impossible proposition at all.

"Indeed, for both levels of government surpluses are likely to remain at best razor-thin without deliberate efforts," Mr Swan was reported by the National Times as saying during his speech on Wednesday before the Australia-Israel Chamber of Commerce in Sydney.

Also, Treasury Chief Martin Parkinson reported on Wednesday that corporate tax jumped only by 4.5 percent during the first six months of FY 2011-2012, alarmingly creating the impression that the government will likely missing its May budget target increase of 21 per cent, seasonally revised.

Mr Parkinson attributed the shrinking tax collection to impacts carried over from the last global financial crisis, recovery from which, he added, would take some time.

Mainly due to the last GFC, Australia's capital gains tax collections have been dwindling over the past few years while the cautious spending behaviour of consumers resulted to lesser GST revenues for the government, the Treasury boss said.

Also, depreciation has largely shaved off considerable amounts from the taxes collected by the government on mining projects while non-mining sectors at the same time have been struggling, diminishing their tax payments in the process, no thanks to the rising Australian dollar.

Economists have been blaming the mining boom for the high value of the local currency, which also spawned what experts characterised as a two-speed domestic economy.

And the long-term prospects appear not rosy at all as Mr Parkinson noted that by 2050, Australia's working age would be decimated by more than 50 per cent, painting a picture of further difficulties for the government to effectively increase its revenues.

Mr Swan, however, remains undaunted as he pressed on that weak tax collections will not deter the government from realising the surplus it had pledged for 2013.

He clarified that company tax collections over the past few years were actually rising but the levels were not line with projections earlier made.

Still, going for the surplus next year "would send a very clear message to the world that Australia is in good nick," Mr Swan stressed.

The economic expansion of 2.3 per cent recorded in 2011 was way below the 3.25 per cent earlier forecast by the government, Mr Swan admitted, which was on top of the mixed economic pace seen on Australian states and territories.

Those numbers reflected the wide differences on the economic performance of the mining regions, which grew by double-digits, while other areas either posted modest growths or stagnated.

"It certainly does reflect patchiness in our economy and pretty rugged global economic conditions at the end of last year," the treasurer conceded.

But he asserted "there is nothing in these numbers that deters the government from bringing down a surplus in 2012-13, although obviously this makes that task more difficult."

Overall, the Australian economy currently sits on solid numbers, considering both the local and global uncertainties that were in effect since last year, Mr Swan said, adding that the surplus remains in clear sight with the government adopting deep spending cuts.

In the face of numerous challenges ahead, Mr Parkinson echoed Swan's stance.

"With muted growth in tax receipts projected for much of the next decade, Australia will need significantly greater expenditure restraint in the decade ahead than was seen in the first half of the 2000s," Mr Parkinson said.