The debate over the future of Holden has turned to how much of a flow-on effect the car maker has to other parts of the economy.

Treasurer Joe Hockey has talked down the broader impact on the economy if Holden stops making cars in Australia.

Holden is considering its future after 65 years of making cars, as it faces a high Australian dollar and other cost pressures.

Labor, the Greens, unions and the automotive sector have argued if Holden pulls out it would have a flow-on effect for hundreds of thousands of related jobs.

Holden says it generated $32.7 billion in economic activity in Australia from 2001 to 2012, having received $1.8 billion in assistance over the same period.

“The numbers involved in employment are greatly exaggerated when it comes to the motor vehicle industry,” Mr Hockey told Fairfax radio on Wednesday.

Mitsubishi had pulled out in 2008 and Ford planned to go in 2016, but “the world has not come to an end”, the treasurer said.

Half of the parts used by Holden were imported.

Mr Hockey said it was “incredibly frustrating” that Holden had refused to confirm its future plans.

Acting prime minister Warren Truss on Tuesday wrote to Holden boss Mike Devereux urgently seeking clarification of the company’s future.

Toyota workers will vote on a new workplace agreement on Friday, which the company says is crucial to it boosting productivity and getting costs down.

Unions say the agreement must come with a new commitment from Toyota that it is in Australia for the long-term and guaranteed support from the federal government.

Mr Hockey said the car industry workforce needed to be more “flexible”.

Asked what sorts of things should be done, Mr Hockey said: “You can have different work shifts, you can get rid of union picnic days and various other things.”

“They want to be more competitive but everyone needs to work together to make that happen, including the unions.”

The government says it is awaiting for a report from the Productivity Commission into the car industry, due in March 2014, before making any new policy decision.

Labor frontbencher Tony Burke said this contradicted Mr Hockey’s call for Holden to immediately come clean on its future.

“It’s no wonder that big companies are saying how on earth do you deal with a government that keeps changing the goal posts, that’s ripped $500 million out of support for the car industry and is changing the rules day by day,” he said.

Opposition industry spokesman Kim Carr, who helped negotiate a post-2020 assistance package for Holden before the September election, said the industry’s future could be secured for “considerably less” than $150 million a year.

Mr Hockey said the government had put $1.4 billion “for future years” on the table for Holden and Toyota.