Weatherill says subs jobs will flow now

South Australian Premier Jay Weatherill says jobs will start to flow almost immediately following the decision to build 12 submarines in Adelaide.

Mr Weatherill says the decision confirms SA will have a high-tech naval shipbuilding sector for decades to come and is an example of the state transitioning from the old to the new economy.

"It is up to us to grasp this opportunity," Mr Weatherill said on Tuesday.