South Australian Premier Steven Marshall says voters will focus on an improved local economy and how well the state has handled the pandemic, as he glossed over turmoil in the Liberal Party after a defector who resigned to become an independent was installed as Speaker in an extraordinary midnight coup.

For Mr Marshall, who has run a minority government and been widely credited with doing a robust job in steering the state through the pandemic and keeping the economy largely open, the coup was an embarrassing turn of events.