Adelaide's massive submarines win won't be enough to prevent more than 600 shipyard workers from losing their jobs by year's end.
Government-owned shipbuilder ASC has confirmed about 640 jobs will be lost at its Port Adelaide yard as work winds up on the Air Warfare Destroyer project.
ASC chief executive Mark Lamarre says the job losses will come despite ASC's likely involvement in the offshore patrol vessels build from 2018.
"The OPV is the only program that has been announced that will affect our workforce between now and 2018," Mr Lamarre told a senate committee.
"Those 640 jobs that we talked about, irrespective of OPV, will be reduced."
Independent senator Nick Xenophon said the decision to build the navy's new supply ships in Spain was indefensible.
"The government has known since its first day in office of the jobs `valley of death' in naval shipbuilding," he said on Friday.
"Yet it has recklessly entered into a contract with a Spanish company to export over half a billion dollars of jobs to Spain, at the expense of hundreds of Australian shipbuilders."
ASC said it had not yet been briefed on the decision to contract French company DCNS to build the next generation of submarines.
The number of workers employed by ASC at Port Adelaide is likely to bounce back when the submarines build commences in the early 2020s.
