The Australian Manufacturing Workers Union has criticised federal MPs for failing to meet a delegation of car workers in Canberra this week.
Manufacturing and component workers boarded early flights home on Tuesday after unsuccessfully requesting meetings with Prime Minister Tony Abbott and other senior Coalition MPs.
The workers were trying to persuade the government to take urgent action and commit more funding to the industry, as the Productivity Commission prepares to hand down an interim report on automotive subsidies on December 20.
Australian Manufacturing Workers Union South Australian secretary John Camillo said the delegation came away from the meetings disappointed.
"We put in requests to speak with Tony Abbott, Joe Hockey, Christopher Pyne, Ian Macfarlane and so on - unfortunately only one person showed an interest and that was [Industry Minister] Ian Macfarlane," he said. "Originally, Mr Macfarlane only had 30 minutes but then he stayed there for an hour to listen to every worker's story.
"From Labor we managed to get Kim Carr, Anthony Albanese and Bill Shorten, and so on, but the key message from the Coalition was that unfortunately a lot of them just never showed up for one reason or the other."
The delegation was made up of representatives from Toyota, Ford and car parts manufacturers. Holden decided not to release representatives from its factory floor to attend the talks.
Federal Parliament is sitting in Canberra this week, with Senate estimates occupying much of Monday and Tuesday's agenda.
Mr Camillo said he was disappointed that, despite two weeks' notice, the workers were not allocated one-on-one time with other senior Liberal MPs.
A spokeswoman for Mr Hockey declined to comment on why he wasn't available to meet the workers.
"We were hoping that we would get some of these pollies to listen to what these workers had to say," Mr Camillo said. "And if not, at least some of their key staff would have come over to listen to what these workers had to say. But that wasn't the case."
Meanwhile, the majority of workers at Holden's Melbourne engine plant returned to work on Tuesday after the Fair Work Commission ordered them back.
About 200 workers had taken unauthorised industrial action over a dispute with the car maker involving redundancy payments.
Staff are expected to meet early on Wednesday morning to vote on whether to accept a new offer Holden has made on redundancies.