The Federal Government could be shackled to the $150 billion debt racked up fighting the global financial crisis for an extra decade unless the economy starts accelerating.
Treasurer Wayne Swan's May Budget is set to confirm a further delay in the date the Commonwealth is projected to be in a no-net-debt position.
The Government was left in a net debt-free position on taking power from John Howard but the Budget plunged into the red as the biggest economic downturn since the 1930s swept across the globe.
Net debt currently stands at about $150 billion.
The Government has set out a timetable for a return to a net debt-free position. In the midyear Budget update this was forecast to be the start of the 2020-21 financial year.
It was predicated on a small surplus this year, ramping up to record-size surpluses by the end of the decade.
It also required government spending growth to be just 2 per cent a year and the economy to grow at least 3 per cent a year.
But since then Mr Swan has had to abandon his promise of a surplus this year with a deficit of at least $5 billion likely. He has also failed to promise a surplus for next financial year.
A deficit this year and smaller surpluses into the future, coupled with other threats to the Budget and slower economic growth, has ensured Mr Swan will have to push out his debt-free timetable.
Stephen Koukoulas, former economic adviser to Prime Minister Julia Gillard, said much hinged on how the global economy panned out.
He said economic growth above trend, low unemployment and a strong performance by Europe, China and the US would all boost revenues to Canberra, which would then enable debt to be paid off quickly.
But there was also a substantial risk that the current projections were too optimistic.
"You could see it taking another five, another 10 years, even longer, before it gets back to no net debt," he said.
"Whoever wins the next election, and beyond that, is going to have to keep a very tight hand on fiscal policy - and that's if there's no repeat of something like the GFC."
Treasury officials have warned both sides of politics of the troubles they face trying to pay off the debt without major assets to sell and further pressures on the Budget.