Taxpayers can expect to see a modest set of savings rather than dramatic cuts to improve the budget's bottom line.
Deloitte Access Economics says the upcoming "bread and butter" budget will focus on pruning waste and tightening spending.
"It's always easier to make cuts to the pet projects of your opponents, and even better when those cuts come years away from an election," Deloitte's Stephen Smith said.
Treasurer Jim Chalmers said he was going through the budget line by line to identify wasteful spending commissioned by the coalition government.
Dr Chalmers said cutbacks would hit some portfolios harder than others.
"Some have been more wasteful than others over the course of the last decade, and inevitably, you'll see that," he said.
Deloitte also said the government should look for other ways to bring in revenue rather than scrapping income tax cuts.
Mr Smith said the preoccupation with the stage three tax cuts and broken election promises was overshadowing the need for serious structural budget repair.
He also said stage three tax cuts were "decent" but not necessarily "good" policy.
"By reducing the marginal tax rate that applies to income over $45,000 from 32.5 cents in the dollar to 30 cents, the stage three cuts provide relief to most taxpayers," he said.
"But by extending that 30 cent rate up to $200,000 - abolishing the 37 cent rung of the income tax system in the process - the policy primarily advantages high income earners."
Mr Smith told AAP income tax represented nearly half of federal taxation revenue and this ratio was creeping higher.
He said there were several other ways to raise revenue to fund worthy spending priorities, including taxing carbon emissions better, clawing back generous superannuation tax concessions and altering the capital gains tax discount on properties.
The economist said Australia's budget was in a much better position than other nations but warned the recent boost to government coffers was only temporary.
"The upswing in revenue is entirely the result of cyclical serendipity - a clear example of passive budget repair," Mr Smith said.
"That passivity is serving Australia well for now, as the path back from some very large deficits becomes clearer."
