SA defence work must be earnt: minister

Lucrative defence contracts are won, not gifted, the South Australian government is reminding the state's defence industry.

Defence industries Minister Martin Hamilton-Smith says firms operating in the sector must remain competitive to land contracts and not rest on their laurels.

Major defence projects soon to kick off in South Australia include the $3 billion construction of 12 offshore patrol vessels at Port Adelaide from 2018.

A $30 billion program to build nine "Future Frigate" ships will begin in Adelaide from 2020, followed by the $50 billion construction of 12 submarines from 2022.

"There's every reason to be excited about these projects and plenty of opportunity to get involved in the supply chain," Mr Hamilton-Smith said in a statement on Tuesday.

"But the opportunities won't just fall into the laps of firms; they're going to have to compete for it. If we sit back and wait, we'll miss out."

Mr Hamilton-Smith said the next 20 to 30 months will shape how the state's defence industry benefits from the next few decades.

He will address more than 70 firms at a DefenceSA forum on Tuesday.