Victorian Premier Denis Napthine has refused to back the Federal Government's position on the car industry, amid fears Holden will stop producing local cars without a new funding commitment by Christmas.

South Australian Premier Jay Weatherill says he believes in Australia in 2016 unless new funding is promised.

The Federal Coalition went to the election saying it would cut $500 million in industry assistance.

But when pushed by reporters, Dr Napthine would not say if he supported that approach, or whether he supported current subsidy levels.

"We will continue to work with the car industry, the Federal Government and the South Australian Government in the best interest of the car industry," he said.

"The answer is we will work with the Federal Government and the car industry to secure the future of the industry."

The Victorian Automobile Chamber of Commerce is pleading with the Federal Government to do all it can to keep the carmaker here.

Spokesman David Purchase says ongoing subsidies are vital to the future of local car production.

"As a government and a community, we need to decide, do we want this industry in this country or not," he said.

"If we do, then we are going to have to support them like every other government does where there is an automotive manufacturing capability."