Workers fear Ford might stop making cars in Australia sooner than its late-2016 deadline, with the company winding back production amid a sales downturn.
Ford will in June start to reduce production by a third, with 300 positions to go at its Victorian plants by the end of the year.
Workers say it's a "kick in the guts", as they had hoped to stay until Ford stopped making cars at its Broadmeadows and Geelong plants in October 2016.
Australian Manufacturing Workers Union (AMWU) vehicles division national secretary Dave Smith said Thursday's decision was not a complete surprise given sales trends, but it created tremendous uncertainty for workers.
Mr Smith said the question was whether Ford could continue producing cars in Australia until October 2016 as planned.
"That is a real fear obviously and that has considerable impact for the component industry," he said.
"If the component industry collapses, the automotive industry could collapse with it."
Victorian Automotive Chamber of Commerce executive director David Purchase says Ford must compete in an extremely tough and competitive world market.
"I personally would not be surprised if we see a quicker slowdown or reduction than was first envisaged."
Ford Australia director of communications Wes Sherwood said the company said in May that it would match production with demand along the way before local manufacturing ceased.
"Certainly the market continues to shift away from larger vehicles and that trend has increased throughout the year last year," Mr Sherwood told AAP.
"Our intent is to produce through October 2016 and we will constantly monitor our operations and if there are any major disruptions we would look and have to perhaps re-evaluate that plan."
Victorian Manufacturing Minister David Hodgett said it was always a concern that sales might decline after Ford announced it was stopping local manufacturing.
"Ford want to continue and are committed to continuing production right up until 2016, but that is, of course, contingent on their sales figures, being able to continue to manufacture those vehicles."
Focus is now on Toyota, after Holden announced in December it would close its Australian manufacturing operations.
Mr Purchase says it will put more pressure on the federal government to ensure Toyota remains, and it would be naive to think car manufacturing could continue without government support.
The AMWU urged Prime Minister Tony Abbott to step in.
"(The government) needs to come out, it needs to support Toyota, it needs to support the supply chain in Victoria, it needs to ensure that the 30,000 jobs in Victoria that rely on the automotive industry are maintained," Mr Smith said.
Mr Abbott said people should be looking at the whole employment picture, not just one dimension of it.
"Any job losses are deeply regrettable," he told reporters.
"The government's job, though, is to ensure that the overall economy is strong and the right conditions are in place for employment to expand."
Opposition Leader Bill Shorten said manufacturing was a viable industry in Australia if the government supported it.
"It seems to me the Abbott government has thrown up its arms and given up fighting for Aussie jobs," he said.