Hundreds of people took part in a union march in Adelaide late last week to demand that the Federal Government build submarines in South Australia.

South Australian police had to issue a traffic warning for motorists to as the march rolled towards Parliament House on North Terrace from Victoria Square.

It was organised by the Australian Manufacturing Workers Union (AMWU), and ended with a large crowd protesting outside federal Industry Minister Christopher Pyne's office.

AMWU assistant national secretary Glenn Thompson said the announcement earlier this year that the subs would be included in a continuous build program for future naval vessels would still see shipbuilding workers will lose their jobs before Christmas.

“The clear message from workers is that while the continuous build program is a welcome development, what they most need is certainty and job security ahead of the changes the government has promised for the shipbuilding industry,” Mr Thompson said.

The rally was on just a week after the AMWU revealed its “Subs=Jobs, build them all here” billboard advertising campaign in Adelaide.

“Jobs are being lost and more are at risk throughout the industry, at major defence contractors and smaller companies in the supply chain,” Mr Thompson said.

“We can't expect these workers to wait around on the dole queue for years while the Government takes its time to decide when to start building new frigates and Offshore Patrol Vessels.

“It is clear these projects need to be brought forward and with the Landing Helicopter Dock and the Air Warfare Destroyer projects winding down, it's time the Government bit the bullet and took a decision to support the shipbuilding industry.”

The Federal Government says its ‘competitive evaluation process’ for the submarine build is still underway, but many expect a few more details in the near future, with the release of its Defence white paper.