The government is still negotiating with key cross-benchers on some of its most controversial policies – including the $14 billion social security bills and $2.2 billion fuel indexation changes – despite Treasurer Joe Hockey revealing last week that the 2013-14 budget deficit was $30 billion bigger than expected.

Mr Hockey said on Thursday the final budget deficit for the 2013-14 financial year had come in at $48.5 billion, $30 billion more than forecast, with 60 per cent of the $30 billion deterioration in the bottom line coming from the write-down of receipts, particularly tax receipts.

But Fairfax Media revealed on Monday that almost a third of Australia's largest companies have been paying less than 10 cents in the dollar in corporate tax.

It means the Australian government has lost $80 billion in potential tax revenue for the years between 2004 and 2013, thanks to aggressive tax minimisation strategies used by Australia's biggest companies.

According to a report prepared by the Tax Justice Network and United Voice, 84 per cent of the Australia's top 200 companies listed on the stock exchange pay less than the 30 per cent company tax rate.

And the use of subsidiaries in tax havens is widespread and growing, with almost 60 per cent of the top 200 listed companies using them, according to the report.

Clive Palmer said on Monday that his Palmer United Party senators would vote against four of the Abbott government's most controversial bills, three of which have passed through the House of Representatives and are now in the Senate.

They include the fuel excise indexation, worth $2.2 billion; its higher education reforms, worth about $5 billion; and its controversial $14 billion social security bills.

PUP senators will also be voting against the government's proposed $7 GP co-payment, worth about $3.5 billion, when it is introduced to the Senate.

All cross benchers contacted by Fairfax Media on Monday said they would either vote against the fuel indexation increase or were still unsure how they would vote.

A spokesperson for Mr Hockey on Monday said the government was continuing to work "carefully and methodically" through the budget measures.

"Labor left historic debt and deficits and the Coalition has delivered an economic action strategy to return the budget to a sustainable position," the spokesperson said.

Shadow treasurer Chris Bowen slammed the government for manufacturing a 'budget emergency' and its list of outstanding budget measures.

"The government could have looked at tightening tax loopholes (multinational tax measures) and continuing with Labor's fairer super tax measure for high income earners, but it chose instead the low road of burdening the vulnerable in our community," Mr Bowen said.

Last month, Finance Minister Mathias Cormann said the government's most contentious budget measures were not due to take effect until July next year or later so there was plenty of time to negotiate with cross benchers.