Treasurer Joe Hockey has threatened to go around the Parliament to cut government spending as figures suggest the Budget is facing a $300 billion hole.
Opening a fresh front in his battle to get key Budget spending cuts through the Senate, Mr Hockey said he had alternatives to the measures opposed by ALP, Greens, Palmer United Party and crossbench senators.
Measures including a $7 co-payment on Medicare services and cuts to Family Tax Benefits face opposition in the Senate.
Another $9 billion hole has been blasted in the Budget by PUP, which has vowed to oppose the mining tax if the Government axes measures linked to it, including the low-income superannuation contribution.
Even the Government abolishing the carbon tax is costing the Budget, with other tax cuts - introduced to compensate for its set up - being kept.
Figures compiled by Deloitte Access Economics suggest that if all opposition parties stick to their current stance, the Budget will be $300 billion further in the red over the next decade.
Changes to the Government's Budget for Family Tax Benefit Part B, a lower tax-free threshold and cuts to higher education would cause the biggest long-term pain.
Access director Chris Richardson said slower revenues and more spending, on top of the opposition to key Budget measures, were major headaches.
"The Budget's burning through money right now," he told _The West Australian _.
Even getting some of the contended measures through the Senate would deal a blow to the Government's longer-term strategy of offering tax cuts beyond the next election campaign.
Mr Hockey, whose comments caught many coalition MPs off guard, said he might have no alternative but to cut other - unnamed - parts of the Budget.
"We need to look at other savings initiatives that may not require legislation and I would ask the Greens and the Labor Party - who between them hold 35 votes on the floor of the Senate - to understand there are alternatives for a government," he said.
The Government yesterday also sought to embarrass Labor by introducing a Bill to delay a change in the tax-free threshold, which Labor had signalled it would make law before last year's election. The measure would save the Budget just $1.5 billion over three years. Labor reacted by highlighting areas where the Government might look for savings, including in its Commission of Audit.
The audit recommended abolishing Family Tax Benefit Part B and imposing a $15 co-payment on Medicare services.
Opposition Leader Bill Shorten said voters were upset with cuts the Government wanted.
A NAB survey of people's attitudes towards the Budget, released yesterday, revealed deep anxiety among women, families and low-income earners over its impact.