It's been revealed only a fraction of the $1.8 billion in federal infrastructure money promised for South Australia in last night's federal budget will flow over the next four years.

Key points: $1.8b for SA road and rail announced ahead of budget

$1.8b for SA road and rail announced ahead of budget Only $162m included in federal budget

Only $162m included in federal budget Industry bodies slam budget as 'smoke and mirrors'

The state and federal governments have spent this week heralding the $1.8 billion funding, which includes $1.2 billion for upgrading South Road, $220 million to fully electrify the Gawler rail line and $160 million towards duplicating Port Augusta's Joy Baluch bridge.

But a breakdown of infrastructure funding provided by the federal Infrastructure Minister Michael McCormack showed just $162 million was set to flow by the 2021-22 financial year.

Just $52 million of a promised $177 million has been committed to the next stage of the South Road upgrade, a major interchange over the Regency Road intersection.

Another $50 million has been committed to the Gawler rail line and $60 million towards the Joy Baluch bridge.

There is no money towards future priorities on the South Road corridor.

SA shadow treasurer Stephen Mullighan said if the money flowed as allocated in the budget, that meant none of the projects would be completed by 2021-22.

"It is extraordinary that we would have a Federal Government asking us to believe that they will commit $1.8 billion after the next two federal elections," Mr Mullighan said.

"This money is needed now. We've got projects which are getting towards completion.

Shadow Treasurer Stephen Mullighan, former Premier Jay Weatherill and Labor leader Peter Malinauskas. ( ABC News: Matthew Doran )

"These workers need certainty and a pipeline. This money needs to come in now.

"If any of this money is beyond the forward estimates, this is a dud deal that [Premier] Steven Marshall and [Transport Minister] Stephan Knoll have signed up to."

Mr Marshall said the federal budget provided a good deal for South Australia.

Treasurer Rob Lucas said the State Government would press the Federal Government to accelerate the funding.

"I wouldn't be crying the sky is falling in, doom and gloom, as perhaps some in the community are," Mr Lucas said.

"It's now a process of negotiation with the Commonwealth in terms of trying to bring forward some of that expenditure."

The SA Chamber of Mines and Energy, the SA Freight Council, the RAA and the Civil Contractors Federation SA have combined to slam the budget.

"This year's federal budget is all smoke and mirrors and delivers none of the promise of the pre-budget announcements made on Monday," Freight Council executive officer Evan Knapp said.

"It is now clear that the Commonwealth's commitment to complete the North-South corridor by 2023 will not be met without a change to the budget, which is a great disappointment for all South Australians."