The federal government and Holden have defended recent closed-door discussions on the future of local manufacturing and taxpayer funding.
While Holden is understood to be seeking more than the $275 million pledged by Canberra, South Australia and Victoria, the car maker and the federal government dismissed as "speculative" reports that it was seeking in excess of $200 million.
Holden is in talks with state and federal governments to cement its manufacturing in Australia beyond 2016.
On Thursday, reports suggested Holden had sought an extra $265 million in help, but Industry Minister Kim Carr said: "I don't know where that figure has come from."
He would not be drawn on what the car maker was seeking.
"If a company comes to me with an issue they get the respect that they deserve and confidentiality," he said.
Holden said it would not comment on the funding process. However, it is understood it wants to clarify its funding position before the federal election in September, which could play a pivotal role in the car industry's future.
"To execute this next-generation program there are several milestones we must achieve - the two most crucial being reducing our structural costs and improving productivity in our factory, along with the implementation of a clear, consistent and globally competitive industry policy," Holden said in a statement.
The funding talks come as Holden sits down with unions and its workers to discuss a revised enterprise bargaining agreement, having tabled a $200-a-week pay cut for its 1700 employees at the company's plant in Adelaide.
Holden has said it costs more than $3000 extra to make a car in Australia than overseas.
A senior member of the Prime Minister's manufacturing taskforce, Professor Roy Green, said Holden would need to meet strict requirements to secure more funding.
Professor Green said Holden was taking the right steps to ensure it remained competitive globally.
"In principle, there is a case for some government co-investment in manufacturing in Australia, in order for us to develop areas of competitive advantage, especially from our high cost base in the context of a high dollar," he said.
"Clearly, General Motors Holden is more committed to areas of that program than Ford, which undertook very little transformation let alone improvement of their facilities."
Professor Green said consideration also had to be given to the manufacturing supply chain, which will be hit when Ford ceases local manufacturing in 2016.
Mr Carr said the same stipulations for funding have been in place since the $5.4 billion New Car Plan was introduced.