South Australian Premier Jay Weatherill will travel to Detroit next month to secure the co-operation of General Motors for a plan by a Belgian tycoon to take over Holden's car assembly operations in Adelaide.
Holden is due to close the plant by the end of 2017 but Guido Dumarey and his Punch Corporation have floated a plan to take over the factory and continue building cars.
"An absolute precondition to Punch getting their idea off the ground is the co-operation of General Motors Holden," Mr Weatherill said on Tuesday.
"I want to remind General Motors Holden of their long history in South Australia, of the fact they still want to sell cars here and the fact that a lot of government money over the years has gone into supporting their business."
The premier said he would ask GM to be flexible and offer every support for the takeover and would also remind the company of its obligations to its workforce, including some who had given loyal service for many years.
"I want them to have at the forefront of their considerations future jobs and opportunities for those workers," he said.
The South Australian government has previously cautioned that the Punch proposal still had to clear significant hurdles but described it on Tuesday as the best offer on the table.
The federal government has been more upbeat with Industry Minister Christopher Pyne hopeful a deal could be done.
The commonwealth has also promised that its Automotive Transformation Scheme, which offers varying degrees of financial assistance, would continue if Punch took over the Holden plant.
Mr Dumarey came to Adelaide and met Mr Weatherill and Automotive Transformation Minister Kyam Maher earlier this month but declined to comment publicly on his proposals.