More than 200 BAE Systems staff working on the offshore patrol boat and frigate programs at the Osborne shipyards held a stop-work meeting on Wednesday.

They are fighting for pay increases in line with inflation.

The company has offered a 5.4 per cent rise over three years as part of a new enterprise agreement, the Australian Manufacturing Workers Union says.

"Despite executive salaries and profits going up, workers are being asked to cop an effective wage cut. It's not on," AMWU SA assistant state secretary Stuart Gordon said.

"Family budgets are under more pressure than ever. We have young local families struggling with mortgages and basic expenses.

"Workers and their families need a wage increase that will give them some security for their future."

Touring the shipyards with SA Premier Peter Malinauskas, Deputy PM and Defence Minister Richard Marles told staff the Osborne workforce was critical to building Australia's maritime capability.

"They are critical workers in terms of our national mission, in terms of building Australia's strategic space, in terms of responding to the complex strategic circumstances that our country faces," Mr Marles said.

"What I wanted to say to them today was just that. The nation recognises their service and values it deeply."

But on the question of a new enterprise agreement, Mr Marles said that process would play out "in the normal way".

Australian Associated Press