The federal budget is built on the back of impossibly large tax increases that won't survive the coming election, a new report has warned.
The Deloitte Access budget monitor, released four weeks ahead of the official budget update, finds that on the government's own forecasts by 2021 the typical Australian income will have climbed $6100, but the typical tax take will have climbed $2500.
The tax take of 41 per cent of each extra dollar is way in excess of the typical average rate of 14.9 per cent and the typical marginal rate of 32.5 per cent.
It would push up the average rate from 14.9 to 18.2 per cent.
"I don't think the average Australian - or the average Australian business - has yet realised that the return to surplus is built on the assumption that 2 out of every 5 dollars of extra income will line the government's pockets," said Deloitte Access director Chris Richardson.
"Politically, in the context of elections and byelections, it isn't tenable, which means the forecasted return to surplus isn't tenable."
Known as the 'treasury in exile' Deloitte Access is run by former Treasury forecasters who are able to say what the Treasury cannot. It's findings echo those of the Parliamentary Budget Office, released last month.
"As it happens, we don't think the increase in incomes will be as strong at the Treasury projects, and we don't think the economy will as efficient at turning it into revenue, but that just makes the deficit problem worse."
Deloitte Access is forecasting a wafer-thin surplus of just $2.3 billion in 2020-21 rather than the $7.4 billion projected in the budget. But that forecast allows for no further tax cuts for four years, a scenario Mr Richardson regards as implausible.
A ready reckoner created by Mr Richardson finds it would cost $6.5 billion per year to cut each tax rate by one percentage point, a cost that would climb to $7.3 billion per year by 2020-21. The cost of returning all bracket creep would amount to $12.2 billion per year by 2020-21.
"The official view is one in which the economy does fine and the tax system does superbly," Mr Richardson said.
"The problems are that we think the economy and wages and profits will underperform, although they are doing alright at the moment, and we think the tax system will underperform at turning that extra income into tax.
"Add to that the awful politics of a rising tax take, and we think the government will decide to cut taxes, using what is most likely a temporary over-performance in revenue as cover."
Mr Richardson said he expected the tax cuts to be promised in the lead-up to next year's election, or possibly when the mid-year budget update is released in December.
In The Age and Sydney Morning Herald