South Australia will expand four respiratory clinics across Adelaide amid rising COVID-19 and influenza cases.

The clinics, originally established for coronavirus assessment, testing, and vaccination, will now cater to anyone with mild to moderate respiratory symptoms, including asthma.

The state government will spend $700,000 to ensure the four sites can operate seven days a week until the end of September.

"Expanding these clinics to include people with respiratory symptoms will make it much easier for all patients to get treatment and take pressure off our GPs," Health Minister Chris Picton said.

"This is just one measure we are doing right now to boost capacity and combat the pressure our hospital system is facing amid rising flu and COVID cases this winter."

Latest data shows that South Australian GP wait times have increased by 49 per cent over the past two years to an average four-day wait, largely due to workforce and funding pressures.

Delays are expected to ease with the expanded clinics allowing for hundreds of patients to be seen each week through face-to-face and telehealth appointments.

The expanded operations came as SA reported another 3809 COVID-19 infections on Friday.

SA Health said there had also been more than 7300 cases of influenza reported so far this year.

Deputy Chief Public Health Officer Emily Kirkpatrick said officials still expected the latest wave of coronavirus infections to peak over the next few weeks.

Recent modelling suggested that could push daily cases as high as 6000.

Mr Picton said SA was working to expand the availability of COVID-19 vaccines with a fourth dose now recommended for more people.