SA has 4349 COVID-19 cases, four deaths

Premier Steven Marshall is hopeful SA will hit a peak of COVID-19 infections in the next few days. (AAP)

South Australia has reported 4349 new COVID-19 cases and four deaths.

Premier Steven Marshall says Saturday's figures include 3175 infections confirmed with PCR tests and 1242 from state-issued rapid antigen tests.

He described the figures as a "significant reduction" on the 5679 infections recorded on Friday, which was the first day rapid antigen tests were included in the daily totals and came after a delay in processing PCR tests following hot weather on Wednesday and Thursday.

There are 236 people in hospital - a drop of 10 from Friday's numbers - including 26 in ICU, seven of whom are on ventilators.

Under the SA government's modelling, released on Friday, daily cases are expected to reach between 6000 and 10,000 when the outbreak reaches its peak, predicted for between January 15 and 25.

"The numbers that we're seeing today fit exactly within the model that was delivered yesterday," Mr Marshall told reporters on Saturday.

"I'm very hopeful that we do hit that peak in the next couple of days in South Australia, and then we head towards reducing those numbers."