The state's peak business and employer body, Business SA, has called on the state government to commit to funding a duplication study for the Augusta Highway.
The group outlined its state budget wishlist, encouraging the government to look at further incentives and payroll tax changes for business as well as address infrastructure needs.
Executive director of industry and government engagement, Anthony Penney, said while the Joy Baluch Bridge duplication in Port Augusta had been funded, Business SA would like to see the state government fund a business case to investigate duplicating the Augusta Highway from Port Wakefield to Port Augusta.
"Dual lane access to South Australia's most northern city will increasingly make sense, and it's no different to how stages are being gradually completed to provide a continuous North-South Corridor through Adelaide," he said. "The state government could also consider a staged approach to major regional infrastructure needs."
The push for a business case follows a call-to-action from the RAA, urging the federal government to commit to the corridor's duplication. The state's peak motoring group has listed the duplication as an infrastructure priority ahead of the federal election.
RAA's senior manager of road safety, Charles Mountain, said such a project was a high priority given the traffic - including B-doubles and freight vehicles - that use the road as well as anticipated growth and developments in the Upper Spencer Gulf area.
"The importance of the corridor will increase," he said.
In the last five years alone there have been 199 injuries and 19 fatalities, prompting the RAA to describe the corridor as one of the state's most dangerous roads.