Although there are three years until production in Australia ends, General Motors’ Holden is preparing to sack half its local engineering workforce – 300 people.

According to news.com.au, engineering work on an updated version of the Commodore is almost done and the services of at least half of the test staff will no longer be needed.

Remaining engineers will stay on for another year to prepare one final update before the Elizabeth, South Australia, car plant closes in late 2017 and Holden switches its entire model line to imports.

Engineers facing job loss are based at the test track at Lang Lang on the south-eastern outskirts of Melbourne and at the company’s headquarters in Port Melbourne, the report said.

Though Holden has confirmed a redundancy programme for engineers – which some reports have estimated will see up to 400 job losses – the automaker would not confirm when the job cuts would be made or how many workers were affected.

Closing the V6 engine plant in Port Melbourne in 2016 – a year before car assembly stops – will cost an estimated 260 jobs while the closure of the car factory in 2017 will out another 1,500 employees out of work.

According to news.com.au, up to 600 white collar purchasing and manufacturing workers at Holden’s head office in Port Melbourne will also be made redundant.

About 140 designers will keep their jobs, working on overseas models cars for General Motors.

Holden will keep its proving ground (and a skeleton staff) to do local testing of vehicles developed overseas, the report added.

In contrast, Ford plans to keep 1100 designers and engineers to develop global vehicles once its Broadmeadows car factory and Geelong engine and stamping plants close in October 2016, news.com.au said.