Holden chairman and managing director Mike Devereux said: "The things that we're talking to the union about are things that are near the end of this decade, many years from now, and frankly they're confidential conversations which we're supposed to have in the course of bargaining with our union.
"The next generation Commodore is an Australian car. We engineered and designed it in Port Melbourne. We're going to build it in Adelaide."
He said Holden had an internal plan to engineer things in Australia but would not outline what things or specific car models after 2014.
He said it was difficult today to "continue to manufacture things in Australia with the economic and political climate that we've got" but there was definitely a role for Australia in the long-term plan.
Walton said Holden had chosen not to tell the public about its plans to stop engineering the Commodore in Australia after 2014.
"Australians want their Commodore designed and built here. They don't want to just bolt together a car engineered and largely produced in China, the US or Korea," he said.
"Despite hundreds of millions of dollars of taxpayer money from state and federal governments, it seems that this could be the end of the Commodore as we know it.
"We are calling on the Australian community to get behind our campaign and help to convince Holden to save our Commodore."
Australian Innovation Minister Kim Carr said: "GM Holden specifically has indicated that they are reviewing their options for future models, as all car companies do constantly.
"As the company itself has indicated in media reports, the questions being raised at this time relate to decisions yet to be made on new products that would not be seen in Australia until near the end of the decade."
APESMA media and marketing manager Matt Nurse said: "What we've been told by Holden is that ... the decision will be made in the next month or two and then implemented in the first quarter of next year.
"They're telling us that it will be highly likely that it will be engineered overseas, but they haven't said that publicly - and they haven't denied it, either."
GM Holden senior manager of product communications Kate Lonsdale said Holden was looking at options for the future of Commodore. "There isn't a deadline on this, so no decision has been made as yet, but we need to make some decisions - and some of these will be tough decisions about Commodore, and what our engineers and designers will work on.
"While we are absolutely committed to manufacturing in Australia, it's critical that our business cases are profitable, first and foremost, and for that to occur we need to have co-operation across all the key stakeholders, including company, employees, unions and governments.
"We've got to take into account all those factors to define what is best for Holden and for General Motors moving forward."
The Commodore has been Australia's best-selling car for the past 15 years but sales have dropped with drivers favouring smaller cars.
- Alastair Sloane
