Subs deal spells mixed fortunes for SA, WA

Naval shipbuilding work confirmed for Adelaide will provide defence industry jobs in South Australia "today, tomorrow and for decades to come", Premier Steven Marshall says.

Mr Marshall said a decision to build nuclear-powered submarines and to continue to maintain and upgrade the current Collins Class fleet in SA had cemented Adelaide as the nation's shipbuilding capital.

But West Australian counterpart Mark McGowan blasted the Morrison government for overlooking his state, warning the move would not be forgotten by voters.

The federal government has announced the decision to dump a $90 billion deal with the French-based Naval Group to build 12 conventionally powered submarines, and will instead build nuclear-powered subs as part of a landmark security pact with the United States and the United Kingdom.

Mr Morrison said the commonwealth would invest $6.4 billion to maintain and extend the life of the Collins Class fleet. Known as full-cycle docking, the deal will support about 1300 jobs in SA.

The federal government would also invest up to $5.1 billion in upgrades to the Hobart Class destroyer combat management systems, creating a further 300 jobs in Adelaide.

"There are going to be jobs for today, jobs for tomorrow, and jobs for decades to come thanks to today's announcements," Mr Marshall said.

"These new submarines will be significantly bigger and more advanced, and today's decision recognises the quality of naval shipbuilding in South Australia and our strong relationship with the federal government."

WA had lobbied strongly for the full-cycle docking maintenance work to be shifted to its Henderson shipyard near Garden Island, where the existing Collins Class submarines are based.

The state's Labor premier said the decision by the Liberal-National government was "not in the national interest".

"The six submarines are based here. The crews are based here and live here. The industry is here," Mr McGowan told parliament.

"The shipbuilding and repair industries are stronger here and they are internationally competitive. The industrial capability, the workforce capability, is immeasurably stronger in Western Australia than in South Australia.

"West Australians should not forget this decision today by the Liberals and Nationals that have let our great state down."

SA Opposition Leader Peter Malinauskas said the decision had left jobs and investment under a cloud with the state facing years of delays.

"The Attack Class submarines were announced in 2016 and building works were originally supposed to begin in the mid-2020s," Mr Malinauskas said.

"This means we have wasted at least five years, with the prospect of several more years of delays to come."

Mr Malinauskas said the federal government must answer key questions, including how many jobs the new deal would deliver, how many nuclear subs would be built and when work would begin.

He said the federal and state governments should provide guarantees that South Australia would not be worse off under the new plan.

Mr Marshall said with hundreds of jobs currently up for grabs in the defence sector, many of those working with the Naval Group would be able to move quickly to other shipbuilding platforms.

"It is a tough day for the Naval Group but their employees will be able to transition over to other sustainable defence jobs very quickly," he said.