Foreign subs pose security risk: Shorten

Buying a new submarine fleet from Japan could put Australia's national security at risk, Opposition Leader Bill Shorten has warned.

The Abbott government has signalled it might walk away from an election promise to build up to 12 next-generation submarines in South Australia.

But Industry Minister Ian Macfarlane insists no decision has been made.

"South Australia is certainly still in the mix," he told ABC radio on Tuesday.

He declined to speculate on reports Australia could buy Japanese Soryu-class submarines to replace the navy's six Collins submarines that retire in the 2030s.

Mr Shorten warned that could "irresponsibly put our national security at risk as a maritime nation".

"Submarine and ship building is a strategic asset that we can't let wither and die," he said in a statement, adding no one could predict every threat of future conflict.

Mr Shorten also accused the government of lying to South Australians.

"It's another kick in the guts for South Australia," he said, citing the pending closure of car maker Holden," he said.

Mr Shorten on Tuesday will visit the Adelaide headquarters of naval shipbuilding company ASC which built the Collins submarines between 1990 and 2003.

It was there before the 2013 election that now Defence Minister David Johnston pledged the submarines would be built in Australia.

The government has indicated any Australian modifications of the Soryu subs - including installation of the computer combat system and ongoing maintenance - will be carried out in Adelaide.

The Australian Industry Group says local supply chain companies will be looking for guidance from the government as soon as possible.

"There's been long-held belief and signals from governments of both sides that submarines would be built in Australia," chief executive Innes Willox told ABC Radio.

The Australian Manufacturing Workers Union has warned that thousands of jobs will be at risk if the contract goes offshore.

A final decision is expected in the next Defence white paper, due for release in June 2015.

But there is speculation the government may spell out its basic approach before the end of 2014.

Palmer United Party Senator Jacqui Lambie is angry the subs could be built overseas.

"It takes away our trade skills for the future," she told Sky News.

She believes Tasmania could fit out the submarines.

South Australian Premier Jay Weatherill said the defence minister had reassured him that no decision had been made yet and he had been very positive about the future for submarine shipbuilding in SA.

He told ABC radio on Tuesday that in the lead-up to the federal election last year, Senator David Johnston made it clear the submarines would be built in SA.

"It would be a monstrous act of betrayal if the federal government were to turn its back on those very clear commitments," he said.