Navy submarine and shipbuilder ASC will cut 175 jobs by the end of October from its Osborne construction facility in Adelaide.

Key points: ASC will cut 75 permanent jobs and 100 contractors will finish up

ASC will cut 75 permanent jobs and 100 contractors will finish up Company says it previously flagged job losses between its defence projects

Company says it previously flagged job losses between its defence projects Union says morale is low in the ASC workforce

In a statement, ASC said about 75 permanent positions would be axed and the remaining positions were contractors.

"The positions will be across the structural, electrical, piping, mechanical and operator trade groups," the statement said.

"Redeployment opportunities will be explored and voluntary and non-voluntary redundancy packages will be offered.

"ASC stands ready, willing and able to take part in future shipbuilding projects and retains the ability to do so, evidenced by the recent shipbuilding productivity improvements on the AWD [Air Warfare Destroyer] program.

"However, the company has always maintained that due to the schedules of the AWD, offshore patrol vessel and future frigate programs, some job losses are still necessary before the start of the next program.

"This activity will have no impact to ASC's submarine workforce or planning for the future submarine project."

Colin Fenney from the Australian Manufacturing Workers Union said the cutbacks were disappointing for the workforce.

"The morale down there is pretty low at the moment. They feel like they've been let down once again," he said.

Work slowing on destroyers

In May, ASC told a Senate estimates hearing it would be cutting 640 jobs at Osborne over the next 18 months as work slowed on the Air Warfare Destroyer project.

The head of ASC shipbuilding, Mark Lamarre, said at the time the figure included ongoing employees and contractors.

"We expect by June of '17 ... to be down to 1,130 which would be a 617-person reduction in total numbers and by December of '17 down to 1,095," he said.

Defence Industry Minister Christopher Pyne described the "slowdown" as unfortunate but said the Federal Government had committed to a continuous shipbuilding strategy to create more jobs in South Australia.

"The Government brought forward the construction of the offshore patrol vessels to commence ahead of schedule in 2018 in South Australia," he said.

"We have already announced nine future frigates and 12 submarines will be built in South Australia, work worth over $90 billion."

In April this year, the Federal Government announced French firm DCNS would build Australia's next submarines at Osborne — a $50 billion contract.

DCNS said it would require construction of a huge new factory in Adelaide for the work.

The union warned there might be too few skilled workers when future projects ramped up.

"When we do get this work in the sheds, these skills are going to be required," Mr Fenney said.

"These people may have found employment in between, so they may not want to go back there, and they may leave with a bitter taste in their mouth and not want to work in that industry any more."