Some 950 Holden employees remain at the factory in Adelaide's north — a month out from the site's closure — with many yet to find alternative work.

A Holden spokesperson said about 800 employees had "transitioned" from the factory since it announced in December 2013 that the company would withdraw from Australian manufacturing.

Of those workers, 71 per cent have found jobs, 8 per cent have retired, 4 per cent are in full-time study and 1 per cent are full-time volunteers.

Some 200 were released early into alternative work.

The Elizabeth factory will be locked down to media from Thursday until the last car rolls off the production line on October 20.

Holden is continuing to assist ongoing employees to find alternative work through its Transition Centre, which is located on-site.

Holden said it would not downscale manufacturing ahead of the closure date and would continue to produce 175 cars per day — except the final day as production will finish early for a private celebration.

A public celebration will be held on October 15 for the Holden Dream Cruise at Elizabeth.

People owning a vehicle made or assembled by Holden in Australia are being invited to register for a parade through Elizabeth City Centre, which will be shut down for the event.

There are 1,500 entrants so far.