Comments made by outgoing General Motors CEO Dan Akerson in the US are being seen as ominous for Toyota Australia, set to be the only local car manufacturer after 2017.

According to a report, Akerson told reporters at the National Press Club in Washington it was too expensive to manufacture cars in Australia.

He said: "There were so many factors in (the Holden) decision. Basically you have a low tariff economy, so outside importers to the country had an advantage. You had a strong Aussie dollar and a supply chain that is weaker because of fewer automakers in the country, so there were a number of factors."

Akerson added "the Australian market is expensive to produce there and Mitsubishi and Ford have all gotten out leaving us and Toyota. There is concern about the supply chain, we are concerned about foreign currency, we are concerned about low tariffs and having to compete with people who are building in Thailand [with which Australia has a free trade agreement - ed] and importing into the country."

The report noted that the manufacturing future of Toyota Australia - which has a plant in Altona, Victoria, is under a cloud after Ford announced it would shut its factories by no later than 2016 and Holden's announcement last week that it would close its manufacturing operations by no later than 2017.

Last Friday, Toyota workers won a Federal Court battle to abstain from voting on changes to wages and conditions that Toyota says were crucial to the survival of the Altona car assembly line and engine plant.

At the weekend, prime minister Tony Abbott said Toyota would not get any extra taxpayer cash - or any surplus funds left over from Holden's factory shutdown.

"The lesson of the motor industry is that once you start subsidising businesses you get yourself onto a treadmill," Abbott reportedly told the financial press. "If the price of keeping the car industry is unacceptably high, well, you just have to accept that these are the trade-offs that life sometimes involves."

He added there was "every chance we can keep Toyota but the level of assistance (will be) roughly the same (as before)."