He said the company and the two governments had a "strong mutual desire" to retain Holden's design, engineering and manufacturing capabilities.
But he said there was unprecedented competition for capital investment in manufacturing and product development for the next generation of global vehicles.
"Car makers are investing billions of dollars to develop future vehicles, so it's critical for Australia to have consistent and competitive long-term polices that make this country an attractive place for General Motors and other companies to continue to invest," he said.
Mr Devereux and Mr Weatherill joined federal Manufacturing Minister Kim Carr in talks with GM chief executive Dan Akerson on the future of Holden's operations, including the funding package.
As part of the discussions, GM has agreed to establish a working group to look at increasing opportunities for local component suppliers in global markets.
Prime Minister Julia Gillard said both the federal and SA governments had reaffirmed their support for Australia's automotive sector and the talks in Detroit were another tangible step in the commitment to secure and strengthen the car industry.
She said the government had its "sleeves rolled up" to ensure manufacturing remained a staple of the Australian economy.
Senator Carr said supporting the investment plans of GM Holden and other Australian motor vehicle producers ensured Australia maintained its automotive manufacturing base and a more diversified national economy.
"I have every confidence that GM Holden will continue to make a major contribution to the Australian economy and to those seeking highly skilled and highly paid jobs," he said.
Holden currently employs about 4800 people across Australia including about 2500 at its assembly plant in Adelaide.
The most recent threat to the company's local operations came during the global financial crisis, when a slump in exports and declining domestic sales forced the company to axe an assembly shift and reduce the hours for some production line staff.
The state and federal government helped the company to turn its fortunes around, with funding to help Holden develop and build the Cruze small car in Australia and make improvements to its Commodore range.
Any new funding is expected to help Holden further improve the efficiency and competitiveness of its vehicles and its manufacturing operations.
Mr Devereux said the parties were making good progress on the co-investment plan.
"Holden and GM look forward to working with the governments of Australia on policies and programs to ensure Australia continues to be one of just 13 countries in the world that has the ability to design, engineer and build cars," he said.
- AAP
