The Turnbull government’s final election costings will show a slight improvement to the budget bottom line.

Treasurer Scott Morrison will release the costings on Tuesday, just four days out from polling day.

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“The overwhelming majority of the measures we’ve taken to this election were outlined in the budget and the modest measures that we’ve announced over the course of this campaign will be reconciled tomorrow,” Mr Morrison told reporters in Canberra on Monday.

There would be an improvement in the May 3 bottom line of the budget he said, refusing to say how that would come about.

The coalition’s no-show so far hasn’t stopped the government from taking aim at the opposition over its costings.

Labor is proposing budget deficits over the next four years that will be $16.5 billion higher than those forecast under a coalition government.

It would also spend $27 billion more than the government over the next four years and $100 billion over the next 10 years, Mr Morrison claimed.

Those figures assumed Labor would never spend an extra cent.

“And if you believe that, I’ve got a bridge to sell you,” the treasurer said.

Labor says the government’s budget is built on a “house of cards” because it contains 16 savings measures stalled in the Senate and unlikely ever to pass parliament.

Shadow treasurer Chris Bowen said the so-called zombie measures were the fundamental building block of Mr Morrison’s “fantasy budget projections”.

Opposition Leader Bill Shorten rejected the treasurer’s claims Labor’s budget plans were a threat to Australia’s triple-A credit rating.

“Complete rubbish, the only party in this election who has had the credit agencies question their ability to hang on to the triple A credit rating is the government,” he told reporters in Melbourne.