Federal Opposition Leader Bill Shorten has committed a future Labor government to provide $1.2 billion for the final stage in Adelaide's north-south road corridor.

Mr Shorten says the funding for the South Road work will be included in Labor's first budget, although the cash will depend on a dollar-for-dollar commitment from the state government.

"The road is increasingly congested, plagued by high accident rates and is unable to cater for the heavy vehicles needing to use it," Mr Shorten said as he visited Adelaide on Friday.

"It is not fit for the state's future needs.

"Too many South Australians are spending too long commuting to and from work when they should be enjoying time with their family and loved ones."

The South Australian Freight Council said the final section of South Road would be the most complex and costly to complete and called on the coalition to match Labor's promise.

Chief executive Evan Knapp said the project offered "huge safety, efficiency and congestion-busting benefits for both motorists and the freight industry".

"The north-south corridor is the freight council's number-one infrastructure priority and has been for more than a decade but completion timelines have been slipping," Mr Knapp said.