Between 20 and 30 people finished up at Holden's Elizabeth plant -- with more to follow.
The company announced earlier this year that as many as 100 contract and casual employees would lose their jobs as the plant's production rate was changed to 400 vehicles a day, which equates to around 90,000 for this year.
Holden spokeswoman Emily Perry said no full-time Holden employees have been exited from the business. "A very small number of fixed contracts were completed this week, and not renewed, as we confirmed earlier this year," she said.
Ms Perry also said a number of casual staff engaged by Holden in busy periods were not required. "These are casual roles and might be called on again in the future if/when required - which is the nature of casual work," she said.
Full-time Holden workers will also be voting on their new workplace agreement today and are expected to start moving from afternoon to dayshift in the general assembly plant next week.