Treasurer Scott Morrison is standing by his forecast for a budget surplus in 2021, even as a new report described Treasury's assumptions as "heroic".
Prominent businessman Tony Shepherd has warned the Australian economy risks a "genuine crisis".
In an independent review of the national commission of audit he conducted in 2014 for the coalition government under Tony Abbott, Mr Shepherd said the burden of national debt made Australia increasingly vulnerable to external shocks.
He wouldn't go as far as describing Australia as a 'banana republic' as former prime minister Paul Keating once did, "but I think we do risk a genuine crisis", Mr Shepherd told ABC radio on Monday.
Even though the nation was about to overtake the Netherlands to rack up more than 26 years of uninterrupted economic growth, many Australians believed they weren't getting ahead.
"Unless we can get growth going again, unless we can get growth in real wages going again, unless we can get more permanent and real jobs going again, I think we do risk a real crisis," he said.
He believes Treasury's assumptions for a balanced budget by 2021 are "heroic" because they rely on the maintenance of an expanding economy and the Senate passing measures to support fiscal consolidation.
Asked to respond, Mr Morrison said the government was getting the budget under control.
"We have the current projection to get it back into balance in 2021. That hasn't shifted a day since I have become treasurer and we remain very focused on that," he told Sydney radio 2GB.
The review, carried out by a panel headed by Mr Shepherd through the Menzies Research Centre, finds the budget suffers from a structural deficit and the level of government spending is "simply unaffordable".
"If Australia's structural deficit continues to grow, it will compound the nation's fiscal deterioration and ultimately limit the government's options with respect to its discretionary spending," it says.
Mr Morrison will hand down his second budget on May 9.
Labor and the Greens are urging him to keep the budget deficit levy on the wealthy in place as the nation's finances are still in the red.
The temporary levy - a two percentage point increase imposed on the top marginal tax rate - was introduced in 2014 by Mr Morrison's predecessor Joe Hockey to help get the budget back on an even keel.
It is due to end on June 30.
Greens senator Janet Rice said it was not the time to give a tax cut to wealthy people.
"We know that at the moment the most vulnerable in our society are being called upon to bear the brunt of the government's positions," she told reporters.
Labor senator Sam Dastyari agreed there were other priorities such as funding the national disability insurance scheme, schools and health.
"Removing the deficit levy shouldn't be the priority, these other areas should be priorities," he said.