Shipbuilders have rallied in Adelaide as the debate reignites about where Australia's future submarines and warships will be built and maintained.
About 200 workers filled a CBD street before a Senate inquiry into the future of Australia's naval shipbuilding industry on Tuesday.
On the agenda at the inquiry is the $90 billion program to build the nation's next submarines, frigates and offshore patrol vessels.
Labor Senator Kim Carr, chair of the inquiry, said the federal government had been vague and deflective about where these ships would be built.
"There is a very deep anxiety here that the level of Australian involvement will be minimal," he told reporters at the rally.
"There is increasing numbers of companies and Australians who are very concerned that there is no certainty for them about their place in ... the building of 54 ships in this country over the next 40 years.
"It is time for the government to produce its industry plan and show how Australians will be able to participate and under what circumstances."
Defence Industries Minister Christopher Pyne would not confirm how much of the construction would be done in Australia but said South Australia would get the bulk of the work.
He said the West Australian government, which has indicated it will campaign for more work, can "wish all they like" but the projects will be centred in SA.
"That horse has well and truly bolted," he told ABC radio.
"South Australia can't help but win the lion's share of that $90 billion spend."
Government-owned French shipbuilder DCNS last year won the contract to design Australia's 12 new submarines, which will be built in Adelaide.
Prime Minister Malcolm Turnbull previously said the $56 billion contract was the largest capital project in Australia's history.
But Senator Carr said the latest proposals from DCNS appear to show increasing amounts of work to be done in France rather than Australia.
Australian Manufacturing Workers' Union assistant secretary Glenn Thompson said "the clock was ticking" on local shipbuilding jobs.
"Shipbuilders across the country are over being a political football in this issue," Mr Thompson said.
He said the sending of projects to Spain and Romania will result in job losses at Osborne in Adelaide unless solid commitments are in place.
"We're asking Christopher Pyne to step up now, to give certainty to all the South Australian shipbuilders down at Osborne," he said.
